Tarpaulin/Tarp/Fly Sizes?

[Matthew P]

All;

I have very detailed information on wall (ridge) tents and associated fly's issued to US forces in WW2, it's laid out in field manuals that are available online or in reprints. But what about Commonwealth forces? I'm looking to get a new made canvas fly or two and want to get a historically accurate size. I'm sure Commonwealth armies had flys that were used for sun/rain protection for catering etc the same as the Americans would use a large wall tent fly stand alone as a kitchen or a mess. But I've been unable to find a size reference.

Thanks
Matt