I really don't know how this has happened but Manga in the UK and USA have different sound mixes.
I too purchased the poor quality G.I.T.S. DVD but I actually found the 2005 (REGION 1 USA/Canada) two-disc special edition to be the best quality DVD copy boasting remastered video as well as DD-EX & DTS-ES (6.1 - 7 channel) soundtracks for both English & Japanese in addition to DD2.0 mixes for Spanish, German Italian and French. Most importantly this has properly timed English subtitles.
If you must buy region 2 then the ghost in the shell 2.0 Redux double disc pack is your best bet.
I do own this (bought for 2.0 Redux as I don't have a Blu-Ray Player) and have no complaints with the sync on this one. This release actually features the trailer and making of as before and the DD5.0 English, 2.0 Japanese & now has the 2.0 mix used on the old VHS (English). All-in-all a great improvement on the previous version. Just don't trust the technical specs and info on the back of the cover as these are for the blu-ray NOT the DVD. Just another example of manga failing to provide all we require of them.
Be warned, G.I.T.S. 2.0 Redux doesn't feature a song lyrics/signs subtitle option so you'll have to turn the English subs on at the start of the movie to read the new introduction.