I don't quite know how to put this. How about:
I've got a couple of Meteor 'P's to do and they've stalled because the parts required to make them fit aren't yet available from Laurie. They will be, but I haven't even drawn them up yet, let alone cut anything out...
The two problems are mainly in the expansion link, which is very much smaller than the one Laurie does and the crossheads, again; Laurie doesn't do any small enough. You'll also quite probably need to turn a section out of the front axle to give the crossheads enough space to travel. You'll also need a very short-throw oval crank, which I don't think Laurie does.
It's not a great place to start. The GAs are fairly readily available (which series are you doing?) they're screens 8174 for the short cab, 5602 for the tall cab and 5601 for the pipe and rod (which is good and clear for the motion). The screen numbers refer to the NRM's microfilm list; copies are easy to get hold of (email Search Engine for an order form).
Sorry to be the bearer of bad tidings; it's nice to know that the person who out-bid me will give a good home to the parts in a Southern loco. A SECR 'C' 'D' would have been much easier though.
Steph