Been watching this forum for ages and joined to answer your question re flap bays. I served on Vintage Pair (ground crew) 1982-84 and in that time period the flap bays on XH304 were aluminium as per the wheel bays, though that colour did not apply to all interior surfaces.
Have to say you are doing a great job and can't wait to see the outcome Point to note, and not a criticism in any way, but the instrument panel in XH304 didn't quite match those aftermarket ones you used. The pilot had an additional altimeter directly in front of him with a stopwatch to the left in line with the de-mister pipe for the DV window. The starboard side consisted of the radios and transponder, the radio being set at a slight angle to face the pilot.
When you come to applying decals the pilots names were always on the port side with the ground crews on the starboard. If you are going to do her with the nose open then bear in mind a lot of the non essential stuff was stripped out as we carried our support kit in there, personal baggage was carried in the Meteor.
Enough for now I'd better nip over and introduce myself properly.