Not much use having a splint if his cock has been blown off though? It's only recently that genital shields have been introduced to the current services uniform. Imagine a huge metal jockstrap to be worn underneath what was, virtually, everyday trousers.
I think it is possible that Daisy will marry William, fall pregnant and Mary and Gary will nick the baby and claim it as their own.
Mary will have realised Matts failings in the bedroom dept despite the willy splint and have been plotting for months to get an heir. From somewhere. I don't think she is particuarly scrupulous.
The baby will be found not to be theirs when it grows up with a face like a Jersey Royal.