WW2 British canteen identification

[Jamescusack]

Hi there, I came across this supposedly original WW2 British Canteen and was wondering if anyone could help me in identifying if it is indeed original or in fact a copy. The seller has no information on it but seems to sell a lot of relics and has 100% feedback. Ive noticed that the strap is not nearly as wide as the strap that is evident on the widely used P-37 and it seems to be in very good condition. Any help would be greatly appreciated.