Being like 'Skinner's Pidgeon' I keep doing that which I believe gets positive results. Therefore before washing the car I run 3 in 1 oil along both sides of all of the Beading Strips as recommended in my handbook.
I have always believed that this process produces a moisture barrier to protect the Ash Frame, the worst spot being along the wings under the doors but I have no idea how deeply the oil can penetrate due to the tightness of the fixings?
Interestingly, during the visit to the factory last week I noticed that on current production, at any rate, the beading appears to be touching Aluminium on both sides of all of the joints where the Ash Frame runs for a depth of at least 12mm.
This is due to the amount of aluminium 'edge' that the guys hammer over the wood frame edges.
I have no idea how much 'edge' was used on our car and I will keep on using the oil pre wash, However, presumably the importance of protecting the frame should demand an 'oiling' before going out on a rainy trip?