I was going to reply earlier as you are a young guy who serves his country and probably one of the nicest and helpful blokes on the HFT circuit ... but it seemed pointless as Rob had already sent him on holiday.
I only managed 3 Nationals last year ... but at Kibby there was a lad on the next lane to me with 1 leg ... another disabled person walking with a stick was allowed to shoot lanes out of order so they didn't have to walk all the way back to an extreme part of the course. At Fort there was a guy shooting a springer ( extremely well ) on the next lane who walked with 2 sticks and his shooting colleagues of the day were carrying his kit from lane to lane etc. I shot a National at Rivi a few years back and the lad that shot with me was taken ill and we were allowed by Marshalls to sit out whilst he took some meds and until he felt well enough to continue and finish the course.
It is a sport that goes as far as it can to accomodate everyone that wants to take part.