These days, with his 60th birthday behind him, the Lambourn trainer is known not for the current thoroughbreds in his stable, but a single horse he prepared in the mid-1970s. Walwyn? He's the man that used to train Grundy, is the regular summing up.
Apparent confirmation that he was going the wrong way on the greasy pole came last year when he swapped stables with Nick Henderson, the National Hunt trainer, switching from the high- powered Seven Barrows to the more sedate Windsor House.
The equine team is now down to 40- odd horses, yet Walwyn was eager to stress yesterday that the years had not eroded his talent. 'It always comes back,' he said. 'If you do the right things, keep plugging away and have the right people working for you, it comes back.'
What has certainly never gone is the man's striking and eccentric presence. As you might imagine of a person nicknamed Basil Fawlty, he appears to be all limbs as he strides bow-legged across our racecourses with his arms dangling almost lifelessly by his side.
At yesterday's debriefing he clearly wanted to reply to the whispers about his waning powers. 'I feel like saying don't let the buggers get you down,' he said.
On these occasions it is always wise to be ready for the unusual aside and Walwyn did not disappoint. 'I'll be having something special to eat tonight and it won't be beans on toast, I can tell you,' he said.
'Hamas is in a race in Germany or some other eastern bloc country but I don't think we'll be going for that now.'
Walwyn put the colt's previous poor performances at Sandown and Ascot down to problems with his bit and soft ground respectively, but when asked to explain these niceties at a stewards' inquiry into Hamas's improved running he was less analytical.
'I told them I'm only going to say one thing,' he said. 'That the only thing that makes more fool of a man than a horse is a woman.'
Hamas made fools of most at the July course, where he was allowed to set off at 33-1. Even as the colt forged into a decisive lead two furlongs out, recollection of his past races suggested he was as sure to be reeled in as a struggling trout. But on he went in the hands of Willie Carson to secure another Group One prize for Hamdan Al Maktoum.
This, though, was one of the least expected baubles to arrive in the Sheikh's treasure chest. 'It's a bit of a surprise because he's been running forwards and backwards,' Sheikh Hamdan said. 'We weren't confident, we were taking a chance.'
Walwyn himself was hardly brimming as he legged up Carson. 'I just told Willie to keep going and try to pick up a few,' he revealed.
The Scotsman deserves a large measure of congratulation because he both persuaded the owner to depart from his regular policy of retiring horses at the end of their three-year-old careers and then devised the most productive method for riding Hamas.
'I asked Sheikh Hamdan to keep the horse in training because when he was going seven furlongs and a mile last year I wasn't sure it was his right trip,' Carson said. 'I had the idea that with him being by Danzig I should ride him like Dayjur (the champion sprinter of 1990),' he said. 'He's not dissimilar in that you have to let him run. If you take a tug he's gone.'
Danzig, however, cannot take all the credit for Hamas's victory, for the colt's dam is Fall Aspen, who has produced six individual Group-race winners, including the recent Grand Prix de Paris winner, Fort Wood.
Carson had designs on using this fruitful bloodline himself, and had hoped that Hamas's second career would be at his Minster Stud. This enterprising ride, though, will have frustrated him.
'I wanted to get him for my stud because I thought he was going to turn out to be a good handicapper or Group Three horse,' he said. 'But I've got no chance now.'