Thanks for the answers!
In the good old days of the 70's we were spoilt at the movies because the support film was as long as the main. The film I have mentioned ran for about 1.5 hours, it didn't seem to be a 'B' movie and it is so annoying because I can almost remember it like it was yesterday. This is one of those films which genuinely made me jump and the reason I am trying to locate it. I know that sometimes films released in the US have the title changed when released over here and I am wondering if it was released under another title.
Thanks for all the replies.