Bethsalem, it autopopulate is working some of the time, then you should be OK :-)
You are never going to get all aircraft populating, as this depends on them being in the Gatwick Avaition Society database - used by RB to autopopulate.
If I want details on a specific aircraft that doesn't autopop, then I look it up at airframes.org - if it's not there either, then you're probably out of luck.