"And my question has absolutely nothing to do with the SDSR. Promise."
Yes you can use your ATPL. Speak to Bristol Ground School. No matter where you are in the LASOR wire diagram, you'll need them for something (Air Law, all 14 exams, etc).
In fact, I think I started a thread some time back. I'll see if I can find it.
Try this
http://www.pprune.org/military-aircr...le-i-away.html