While it was the third time in his career with four winners on a card for Richards, it was a first for veteran rider Harding.
“I think I’ve done it twice before. I did it at Perth one day and I may have done it at Wetherby as well,” said the Greystoke handler.
“We’ve had a great day. The last horse [Another Bill] is a lovely horse – I think he’ll make a smashing horse next year.”
Another Bill (11-10 favourite) put the seal on a fine day for the pair when following up his course success on his debut nine weeks ago in the Download The BetVictor Instabet App Standard Open National Hunt Flat Race.
The five-year-old, who was giving weight all round, denied Stuart Crawford’s Irish raider Baby Bach by a head after a pulsating duel up the straight. The front two pulled 28 lengths clear of Jack Steel in third.
Cultram Abbey (7-2) lifted the feature race on the card, the Best Odds Guaranteed At BetVictor.com Handicap Hurdle.
Harding delivered the eight-year-old to challenge the pace-setting Stopped Out in the straight and make a winning move between the last two flights.
Mijhaar, the 9-4 favourite, tried to peg him back but was well held by four lengths. Stopped Out was a gallant third, another three and a half lengths away.
Sir Vinski (8-13 favourite) got the ball rolling for Richards and Harding, although he was made to fight to land the odds in the BetVictor.com Maiden Hurdle in what were testing conditions at the Scottish venue.
The six-year-old dug deep to open his account over jumps by half a length from Calivigny after showing promise when third on his hurdling bow at Newcastle five weeks ago.
Teddy Tee (9-2) displayed loads of stamina to get off the mark in the £25 Free Bet At BetVictor.com Handicap Hurdle.
Running for the first time in a handicap after cutting little ice in three maiden events over shorter distances, Teddy Tee appreciated a sterner test as he led between the final two flights to score by four-and-a-half lengths from Nosey Box.
Perthshire trainer Lucy Normile picked up a double through Cadore and Silverton.
Cadore (14-1) scored by six lengths from Plus Jamais in the Gallagher Handicap Hurdle.