Well, I took a look at all the stuff I had in my shed and decided to call it 1943, I couldn't justify selling off one set of WWII stuff at a reduction to buy another at full price. Sometimes, you have to mull over these things.
There was a sizable American force in and around Cheltenham that allows them to sneak in.
The same scenarios can exist, but in my alternate world the war has not gone well for the allies and the Germans have invaded. No more fantasy than Operation Sealion would have been.