The Rover Repair Operation Manual shows the reserve tap mounted below the fuel tank and also in the engine bay. It would appear that the below the tank mounting was for NADA vehicles. My P6b has box pleat AMBLA trim but the front seats also have large sheepskin covers, like many cars in NZ. They are cool in summer and warm in winter and I am sure they are more comfortable than straw as favoured by Demetris.