Hi Katrina,
It sounds very much like he was sent to prison.
I'm afraid that I'm not very knowledgeable regarding such establishments and Dear Old Auntie Google was not very forthcoming when I asked about prisons near Park Royal. I was quite persistent but she was having none of it; must have been having a bad day, I guess.

My maternal grandfather could, most probably, have helped us out here. As a former resident of several prisons, who spent a great deal of his life at His Majesty's Pleasure (I'm talking pre-Queen Elizabeth II), I'm sure he was very familiar with them. But he's been deceased for 57 years now so we can't ask him!
I'm also no expert on military matters but there are more than a few Rootschatters who are...I expect they'll be along shortly and respond to your post.
It's quite possible, too, that among the Rootschat community there are members who know all about the prison service. (Hopefully as employees/ex-employees; but maybe also those who've experienced a bit of porridge themselves.) Let's keep our fingers crossed that they chip in too.
If you don't get a response after a few days - which is pretty unlikely - ask the Mods nicely and they'll move your thread to the World War One Board. (It's best not to post on more than one Board at a time as this can lead to Rootschatters wasting their time duplicating each other's efforts as they assist you - which is obviously a big disincentive.)
Sorry I couldn't be of more help. I hope I've kept you entertained for a minute or two and that my post assists in keeping your thread near the top of the board, where it's bound to get more attention. Good luck.
Rgds,
theirchild