Theoretica? Are you watching? A follow up on military service issues

So, below is a response to some points made by anonymous reviewer Theoretica regarding how I'm handling getting Peter into the service.  There are some pretty significant spoilers below -- though, in truth, anyone who has studied certain key events in WW2 can already see where this is going based upon Peter and Asim's conversation in Chapter 2 in the train station.  So, I'll post here in the hope that Theoretica (or someone else with an in depth knowledge of enlistment, conscription, and military service in the UK in 1943) can help.  If not, I'll rely on the Big Cat In The Machine -- Felus Et Machina

( So, Theoretica, I need to get Peter from Point A to Company D )