When the screens leak, and the cars have been sitting for a long time, the carpets stay wet, and the seat runners rust badly, stopping the seat sliding, and if the seat doesn't slide, you cannot get at the bolts holding the runners from the floor, so the only option is to drill the 4 bolts per seat from underneath, which is tiring, often damages the oval threaded bobbins mounded into the shell, and breaks many drill bits.
Having got the bolts drilled out of 4483R, the seats were repairable, but the seat runners were so badly rusted, that they cannot move, even after overnight soaking in acid.
So I went in search of replacements, and this is what I found:-
http://www.ebay.co.uk/itm/like/371062257359I have ordered two and will report on their suitability. They will probably need stretching apart to get the right spacing, but I am hopeful they can be made to work with new holes drilled and large penny washers to spread the loads.
Alex in Norfolk.