What you forgot to add into the ingredients were:
The highest proportion of 110/90 type motors are used in the farming community, with the highest per capita being where the smallest farms are - the South West of England; Somerset, Dorset, Devon and Cornwall. Warmest part of the UK so less road salt is a bonus.
Motorways in the UK are massively overused, with speeds and driving conditions that don't suit older LR's. Go on the back roads
I live in a village of 475 folk in 170 odd houses, there are 34 landrovers, of which only 2 are D3's. There is one RRSport but he also has a '50 Series1 so he's okay. There are a couple of Series three's - one with RRC axles and a 200Tdi. 3 of the 90's are '84 and original; 2 of the 110's are 83/84 and original. Small farming community you see.
Sadly folk in the big cities have cottoned on to the fact that you folk over the North Atlantic are happy to pay big bucks for dodgy crap. And keep on doing it, time after time. Makes it worse when decent honest folk from the International Brotherhood of Land Rovers offer to help and get ignored - but such is life