The four-year-old was trained by Andrew Slattery on the Flat as a two- and three-year-old before making his hurdling debut in December.
Second in a Cork maiden at the first time of asking, the gelding then went on to claim a competitive 20-runner maiden at Punchestown on New Year's Eve.
Defeating Gordon Elliott's Calico by two lengths, Sir Allen jumped fluently and showed promise among a large field filled with runners from the leading stables.
"We were thrilled, from the first time he jumped a hurdle he showed he liked it and it was great that he carried that onto the track," Slattery said.
"He's done what he was showing at home. He had a good run at Cork, we thought he'd improve from that and he did, I'd say.
"He's a lovely horse who'll jump a fence in time. He was well capable of winning more on the Flat, he should be a good fun horse.
"He had a little injury early on last year and missed the early part of the season, that put him on the back foot as everything was a bit rushed to get him ready for the later part of the Flat season, but from the first day he jumped a hurdle he seemed to love it."
The Dublin Racing Festival or a Naas outing are next on the agenda, and the handicapper's assessment of the horse's performances is then likely to inform his target at the Cheltenham Festival.
Both the Boodles Juvenile Hurdle and the Triumph Hurdle could be on the cards, with the former a handicap contest and the latter run off level weights.
"He'll have one more run, either at the Dublin Racing Festival or in Naas in February, it'll be one of those," Slattery said.
"We'll see what the handicapper does and that will tell us whether we'll go for the Boodles or the Triumph - it depends on where the handicapper puts us."
Sir Allen is owned by the Eight Star Syndicate, from whom Slattery used to train Dinkum Diamond after his spell in England with Henry Candy.
Slattery explained: "The syndicate that owns him used to have a very good horse a few years ago called Dinkum Diamond, that used to be trained by Henry Candy, hopefully this is another nice horse for them."