The North American DVD region is region 1, the UK is region 2, there's no difference except that region 1 discs are usually NTSC system and region 2 discs are usually PAL system.
Supposedly, region 1 discs can only be played in region 1 (North America etc.) and region 2 discs can only be played in region 2 (UK etc.), but many people in the UK (including myself) are able to play region 1 discs and discs from other regions.
Americans can usually only play region 1 NTSC discs because NTSC TVs can't display PAL pictures, but most modern PAL TVs can display NTSC pictures.
The Wicker Man wooden box set was a limited edition for North America on region 1 NTSC format, Amazon.com still has them
(See here).
I have two of these sets, one to watch and the other one is still sealed.