No one expected Sarah Ferguson to stay out of the spotlight for long and, shrewd as ever, she chose exactly the right moment to appear.

Thursday's memorial service for her former lover and long-time confidant was an occasion from which few could reasonably expect her to stay away.

All the same, some will wonder if her appearance at a thanksgiving to celebrate the life of motor-racing figure Paddy McNally veered more from bold to brazen.

She had, after all, prudently avoided McNally's funeral service in July, sending her daughter Princess Beatrice to represent her. But for the woman known in the Royal Family as the 'red setter', the service in Knightsbridge was the perfect opportunity to reacquaint herself with the public and the public with her.

If the timing was a simple coincidence, it was also extraordinary. It is almost a year to the day since the cosseted world of privilege and comfort she had for so long taken for granted came crashing down. A year in which she lost both her position and her title as Duchess of York, her home and her purpose as charities and business rushed to sever all links.

Unlike her ex-husband Andrew Mountbatten-Windsor who, although stripped by his brother the King of his princely title and HRH style and forced to vacate his home Royal Lodge, was given a home on the Sandringham estate, Fergie was offered no bolthole. She was, in short, left to sink or swim. And many thought that, deprived of the trappings of royal life to which she had so greedily become attached, Fergie would sink.

But there has always been a resilience to the one-time duchess whose entire royal life has been a saga of overcoming adversity that she usually brought upon herself.

So, after this bleakest of years there was something impressive about her willingness to be seen at such a high-profile gathering. She was, of course, surrounded by family: both her daughters Beatrice and Princess Eugenie were at her side along with their husbands.

The fallout from their parents' disgrace has left its mark on the sisters, whose loyalty has at times been stretched to breaking point. They too have been sucked into the maelstrom of their mother and father's ruinous folly.

Yet somehow there was no mistaking that familiar iron-clad self-belief that Fergie has always possessed as she took her seat in the pews at St Paul's church, just along the road from Harrods. She didn't shrink from the cameras but the smile she proffered was from a careworn face that reflected the toll that the last 12 months have taken.

For someone so irresistibly drawn to the trappings of royalty and the attendant limelight, the absence of such attention must have been as difficult to cope with as the pimpernel-like existence she has had to chart for the past year.

Until Thursday, she had only been seen once in 15 months – when she was discovered holed-up in a remote £2,000-a-night spa in the Austrian Alps, where friends loyally described her self-imposed solitude as 'recalibrating'.

This departure into near invisibility for the once gregarious Fergie has triggered considerable speculation. Was she writing a memoir – another to add to the two she had already penned – or rehearsing for a tell-all interview that some said would 'blow the doors off' the House of Windsor for good? Or even planning a comeback? Or was she, finally, embarking on a lengthy period of introspection that has been so lacking for so long?

Her appearance battered but not beaten and just a stone's throw from Buckingham Palace suggests another possibility. That, perhaps, she is hoping to resume a royal life of sorts. Her daughters were not the only royals in attendance, also there was Princess Anne's son Peter Phillips who, like the late McNally, has interests in motor sports.

It may have been fortuitous that the King was out of the country and thousands of miles away on a Commonwealth tour in the Caribbean for the moment that his former sister-in-law should choose to reinsert herself with London society.

All the same, some will say that such a move is premature. The stench of the Jeffrey Epstein affair still swirls around her ex-husband, and her presence is an uncomfortable reminder that she too was no innocent party in the sordid saga.

The cache of emails published by America's Department of Justice earlier this year revealed deep financial, personal and affectionate ties between Sarah and the paedophile businessman.

In one she described him as 'the brother I have always wished for'; in another she gushed: 'You are a legend. I really don't have the words to describe, my love, gratitude for your generosity and kindness. Xx I am at your service. Just marry me.'

But much more damaging were communications in which she described Epstein as her 'supreme friend' and apologised for publicly criticising him.

Her most damning dealings, which earned her considerable public opprobrium, involved her daughters. Just days after Epstein was released from a 13-month sentence for soliciting an under-age girl for prostitution in 2009, Ferguson took Beatrice and Eugenie, then aged 20 and 19, to meet him, flying to the US on air tickets he had paid for.

On Thursday, she looked less edgy than she had back in April at the Mayrlife health clinic in Austria, where the super-rich and supermodels are drawn to its expensive mollycoddling. Perhaps it was the security of being with family and friends, or maybe it was simply that she was honouring the man who represented a less chaotic time.

Before Andrew, Paddy McNally was the man at her side. They met after Fergie was recruited to look after McNally's young sons Sean and Rollo after the death of his wife Anne in 1980. The two became lovers but he never asked her to marry him. He was simply too busy. McNally was then on his way to amassing a fortune earned in partnership with F1 tycoon Bernie Ecclestone with whom he revolutionised corporate entertainment on the world's racetracks when he launched the Paddock Club.

This enabled him to live in some splendour, often in the Swiss ski resort of Verbier where he owned no fewer than three chalets, one of which was euphemistically known as 'Cocaine Castle'. He had his own Scottish grouse moor, a Wiltshire spread – James Bond creator Ian Fleming's former country home – and a substantial villa in St Tropez.

Over these past months, McNally put both his homes in Switzerland and the South of France at Fergie's disposal as she flitted from safe house to safe house lying low. Some have wondered if his final gift was to bestow some of his £600million fortune on her too.

'Paddy was my father figure, 22 years older than me,' Fergie once said. 'He taught me so much about life. Whenever I wanted advice, I turned to him because he was so worldly wise. He seemed to have seen and done everything.'

As she makes her first public appearance back in her homeland, Fergie could do with that advice more than ever.