Well, we decided we could not part but now, old age is creeping in - the front brakes are spongy to the point of a vote of no confidence.
A rolling road test shows the rear brakes to be o.k. but the front are around 35% efficiency.
My local mechanic with 45 + years experience is scratching his head as to the cause. The master brake cylinder and booster assembly have been changed as has the proportioning valve - each time the brake fluid was replaced and the brakes bled.
Booster operation and air tightness under load (5-32 & 5-33) check out o.k.
The replaced parts were second hand but believed to be in good working order, so, could it be the brake hoses ?