Six-times champion Flat jockey Fallon, who hung up his saddle in 2016, gave the Nigel Tinkler-trained Kilbaha Lady every chance over the straight mile, but could never quite get into a winning position.
That honour went to Bell, who gave up riding through injury in February 2018 and is now assisting her partner Philip Makin in his switch from jockey to trainer.
Destroyer had taken the 16-strong field along that raises money for the National Horseracing College and Jack Berry House, but was swamped as the pace hotted up over two furlongs out.
Fallon – riding for the first time on the same card as son Cieren junior – said: “I thought I was going well enough to win, it was just when I asked her to quicken she just didn’t let herself down on the ground.
“I travelled better than anything and thought I was going to win, but we didn’t. It’s all for a good cause, though.”
A delighted Bell said: “It was really good, I think I hit the front too soon, but that was just me getting excited.
“I’m really grateful to Richard for giving me a ride and it’s great to pay him back with a winner. I really enjoyed it.
“I did only just hold on, but that was me going too soon – the horse was helping me out. He was good. The last time I sat on him he was a yearling.
“I’m not as fit as I used to be, I know that much, but we’re quite busy at the yard, so I haven’t done as much prep as I would have liked.”
Fehily, who announced his intention to retire after riding a winner at Cheltenham in March, said: “The trainer told me not to hit the front too soon, but I think I overdid the waiting tactics!
“I got blocked in my run just over a furlong out and I had to switch, it probably just cost me, but he’s run a blinder.
“It’s been a great occasion for a great cause and I’m just delighted to have been asked to take part. Hopefully we’ve raised plenty of money.”