small update:
I have managed to get hold of L & R NOS Sills!!!, and A good forum lad is parting with a spare wheel well, so i am a very happy camper..
Still need a rear boot panel (the one with the petrol cap hole), so any ideas would be great. I might need to go looking at wreckers.
thanks to Jim, the new vent/plenum has been fited. front is new, rear (towards windscreen) original.
and thanks to the forum, my front speaker mounts are being put into place on the firewall:
photos of sills to come, once they are back from the blasters.
Stash.