The internet is a vast space and often very good reference sites can get lost in the ether. Here I have picked out some of the most useful sites for collectors and military historians, I hope they are as useful to you as they are to me:
Web Sites
Karkee Web– Simply the best site out there for British and Empire webbing and accoutrements.
British Military Small Arms and Ammo– Great site for small arms ammunition, identification, history and headstamps.
British Formation Signs– Not by any means complete, but a good overview and covers most of the WW2 formation badges
Gas Mask and Respirator Wiki– Frustratingly incomplete, but this does have the most detail on British gas masks I have found on the web so far.
Blanco and Bull– Wonderfully in depth study of those British Army staples blanco and boot polishing.
NBC– A good page, that is part of a larger site, concentrating on British Cold War NBC kit.
Weapons Online– A site devoted to Vickers and Bren Guns- has a very useful section where you can view and download a large selection of Small Arms Training Manuals.
The Mills Grenade Collectors Site– Another good reference site with lots of information on what all the stamps and markings on grenades mean.
Combat Helmets of the World– This excellent little site has hundreds of helmets from around the worl, great for looking up obscure headwear.
Airborne RAMC This re-enactor site is packed full of information and pictures of WW2 medical equipment. Although its aimed at the airborne side of things, most of it is fairly consistent across the RAMC.
Old Military Markings Very useful page with explanations of the markings found on British and Commonwealth bayonets.
Military Sun Helmets Another great site showcasing the Sun Helmets used the world over.
Wartime Canada Training Pamphlets– This useful site has lots of wartime training manuals to download and look through. Most are Canadian, but the general principles apply across the Empire.
Stable Belts of the British Army– A useful site explaining which regiment each of the brightly coloured stable belts belong to.
Escape Maps This site covers the history and design of RAF and US escape maps form World War Two to the present day.
Forums
BOCN– A very in depth forum looking at all forms of munitions, some great reference stuff on here, especially when trying to identify ammo boxes
Warelics– A good all round collectors’ forum, concentrates a bit much on 3rd Reich for my interests, but knowledgeable posters and a helpful bunch.
wwiireenacting forum– geared towards the living history side of things, some of the posters on here think they know more than they do, but it does have interesting discussions and can be a useful source of information but try and double check anything before taking it as gospel!
British Badge Forum– Pretty much does what it says on the tin. The people on here are real experts in their field and its very unusual if they can’t identify a mysterious badge!
Tales from the Supply Depot 
I have just seen my RAF beer mats on your site, you said you were unsure of the date,
They are from about 1976 and were promotional items given out for recruitment, I was working in Leeds recruiting office at the time