I now know what it is so I thought I better put you all out of your misery!!! I posted the same thread on a pre-cert site that I use and somebody came up trumps.

Monster club 1980

http://www.pre-cert.co.uk/cgi-bin/cms/Film/48369

Sounds very cheesy so probably right up my street. Now all I've got to do is find an old copy to re-live that terrifying moment and discover it really hasn't stood the test of time ;)

Cheers for all your suggestions

Toby