I wrote that sometime ago, and to be honest have forgotten the 20 minutes' worth I watched of the plot, so quote here the review somebody else wrote on the IMDb, who agrees with me!
"A group of students at an elite music school decide to share a flat in order to cut their living costs and have somewhere to practice together. They get into quite a few scraps and adventures, including impersonating a celebrity quintet. However when Mervyn Hughes accidentally sells a catchy pop tune to an advertising agency he risks losing his scholarship unless he and his friends can raise the money to buy the rights back.
With an impressive sounding Carry-On cast featuring quite a few famous names from British comedy I was quite looking forward to this being a gently amusing little piece. Sadly I was fooled and this film turned out to be as weak and unfunny as you can imagine. The plot sees some of the oldest students I've seen sharing a flat; from here the plot has a few adventures, before splitting to be about Hughes' drunken mistakes and Malcolm's attempts to win a conducting prize. None of it really engages and, more importantly, none of it is ever really funny."
And when you read the cast list, you realise it's the script that is crap.
https://www.imdb.com/title/tt0055354/fullcredits?ref_=tt_cl_sm#cast
