Info on aircraft equipment.
I've been pleased by how helpful the RAF Museum at Hendon can be regarding some equipment. They've given me some interesting info before now.
As for the P10, I'm trying to remember the compass in the Mew Gull (G-AEXF), ex Des Penrose, Alex Henshaw etc. But that had a big compass, bigger than the P8. You may wish to contact Breighton to ask them if it's a P10