Good question, after much thought my earliest cinema memory is a film possibly called Journey to the Top of the World at a flea pit in Seaford. I also saw Jaws at same flea pit later on.
Very first memory is of being taken to The News Theatre in North Street (now a Burger King) which used to show non stop cartoons and newsreels. This was in the late 50's so I must have been about 5 at the time.
First proper full length film I remember seeing was Cliff Richard in The Young Ones back in 1961 at The Ritz cinema in Shoreham.
I used to go to the 'Saturday Morning Pictures' at the local Granada when I was a lad, but my first 'grown up' film at the cinema must have been 'Dracula- Prince of Darkness' and 'Plague of the Zombies'. I almost cacked myself! How a bunch of innocent-looking fresh-faced 12 year old kids managed to get into see an X-rated (18) film is something I still don't quite understand!
I've seen both films since, and found them to be disappointing.
Haven't got a scooby. Probably a Lone Ranger thing on a Saturday morning ABC Minors or whatever it was called in Haywards Heath (when it had a cinema). First "proper" film would have been either Star Wars or Grease, whichever came out first - can't be arsed to look it up. Queued from the seafront right round to Russell Road in Brighton to get in for both.