Tommy Trinder was a star in his day and this was meant to be a vehicle for him. I guess if you like Tommy Trinder then this film will have some appeal but otherwise it is at best a quaint and not terribly funny period piece.
The premise of 'army life meets reservists/new recruits' is one that had already been explored and would be explored again. I guess the humour is largely lost on today's folk that didn't have military life as part of the common experience. As others have noted this film serves to highlight what a good film Carry on Sergeant is. Cast aside, I suppose this film could claim that it isn't any worse than 'down amongst the Z-men' but the latter at least has a catchy song in it.
The BFI have taken the trouble to digitally remaster this film and whilst it wouldn't have been top of my list for this treatment, they have done a decent job of it. The anamorphic lens used for the cinemascope-esque wide screen did produce some weird artefacts though; there is quite a lot of distortion at the edges of the frame which I found a bit distracting.
Overall there are other films in this genre which better deserve a viewing than this one.