Hi Martin,
I may be wrong but my suspicions are that you have a real find there.
My understanding of events is:
"The Night" was actually issued twice by Mowest UK. The first issue was abandoned due to faults at the pressing plant and records recalled and destroyed. Thus the first issue is a very rare record.
Of those records in the first press, some were perfect except for one detail - they had no labels - or rather they had labels but these were white and not printed at all. Thus first issues with plain white labels are incredibly rare. As yours is stamped in the same way as the latter issue (it's an unusual font, check the match), my opinion is that it is real.
It is not a pre-release though but a first issue. Manship auctioned one of these a while back but no idea what it fetched. I would think it's pretty bloody close to a one off and therefore, to the right collector, extremely valuable.
What I am a bit vague on is the release numbers. I think that the first issue was 3002 although it may be 3022, I'd check that stamp mark again if I were you. The second issue was definately 3024 though.
Can anyone else add more detail or confirm/disprove the above. I'd like to know and I'm sure Martin would!
Cheers,
John.