He went on to partner Imperial Vic, Totalize and Amisfield Lad for a day to remember at the East Lothian track.
An elated Cook said: "It's been a great day – I've never even had a treble before, so this is something else."
James Ewart described Lord Wishes as "the best horse in the yard" after the five-year-old romped to an 11-length success under Brian Hughes in the Bet & Watch With Racing UK's iPhone App Maiden Hurdle.
The Langholm trainer added: "He enjoys good ground and is from a good family. He has class and will go to Doncaster towards the end of January. One day he will make a lovely chaser and his nickname in the stable is Porsche."
Meanwhile at Carlisle, Tipsy Dara enjoyed the stamina-sapping conditions to land her first course success under Lucy Alexander in the two-mile, four-furlong handicap chase.
The half-length winner is trained by Alexander's father Nick, who said: "This mare is probably better at three miles and she stayed on very, very well.
"I thought as they turned in that she would nearly win and this is her level on deep ground. She certainly gives you everything."
The Alexanders went on to complete a double in the bumper with Standintheband.
Nick Alexander added: "I am delighted, as his owners lost a horse at Aintree earlier in the autumn."