Another point: men that were single were called up before married men. There were general guidelines but that's all they were. I read a true account of a man who was 40 and was called up at the beginning of the war but that wasn't the usual case. And a man might get out of serving if he had a one man business and could show evidence that his business would suffer if he was called. And then there were the conchies. There's an actual list of when an age group was likely to be called. I have it if you want it.

Wodehouse had vision problems and was not allowed to serve in WWI.

I have various reasons for the path my story has taken including the fact that I don't believe Bertie would leave England in its time of need.

Anyway, I'll help you, if I can.