‘Leave your brain’ at the door, we’re told at the top of Delete The Banjax’s fourth Fringe offering. That’s reasonable advice for a revue-type sketch show that’s silly with a frequently entertaining Knockabout charm, but is still far from being consistent.

When they bundle on stage, the immediate thought is that Samuel Champion, Daniel Cook, Gareth Cooper and Caroline May-Jones are kids’ TV presented on day release – trying very hard to fake laughter and good times, but not in a particularly convincing way. That idea never quite evaporates, although some parts of this hour are rather good.

The IRA and Cornish Separatists terrorists who’ve double-booked a kidnapping is funny, as are the brainstorming of alternative names for a couple of well-established products, while the new parents baffled by their baby will strike a cord with any parent who feels they are muddling through, out of their depth. Re-imagining the budget as a romcom, unlikely as it seems, works well, too, and is splendidly acted.

But other sections seems shrill and over-excitable. An over-competitive pub quiz featuring May-Jones going psycho pushes itself on you too much. Talking of which the quartet do like interacting with the audience, sometimes at uncomoftably close range, as well as having fun bantering with themselves.

There are a couple of upbeat songs, too, despite the team’s limited singing abilities. One about summer hits that once sounded great but are now annoying lodges those tracks back in the brain, and a British take on Glee is funny and upbeat, but probably a verse too long.

Yet despite the good moments, and frequently inventive inspiration, the Banjax crew seem to be treading water, with their boisterous energy not offering enough for them to be a must-see in what’s proved to be a strong year for sketch comedy. They need to offer more than their studenty exuberance.