Hi there - I have the compass (P10), a complete wimperis bomb sight, an ammeter, and a hand held compass, if that's what you're looking for? I'm in Watertown MA USA.
Welcome to Spitfire Spares where we specialise in supplying Warbird related items such as spitfire spares, aircarft spares, parts manuals, replicas of spitfires, the V1 Doodlebug and Hurricane, we are the warbird and spitfire specialists.
Also, Bomber Command Museum of Canada - Information has many spare parts for Lancasters. Contact Karl Kjarsgaard to see if you can obtain needed parts in return for a donation or trade.
EDIT: Many Lancaster parts are common across other British planes and I have access to a number of instruments. PM me with a list of specifics if this is what you are after.