The first film is distributed in the UK by Warner Bros. The sequels are handled by Paramount. Presumably this is why only the sequels have been reissued.
The UK WB release of the original is pretty good and easily affordable. Original unrated version (official videos featured the R-rated print) and reasonable extras (trailer, commentaries & 20 min
Making Of featurette). The U.S Deluxe Edition features additional extras.
Friday The 13th.