I just talked to Kev Jones at Jones Springs Ltd and may well be getting leafsprings (incl bushes)from them. It isn't cheap: works out at £120 per front spring / £140 per rear = 520 + VAT = £611 total OUCH!
That's a lot of money, but when you think what you are getting for it in terms of skill, ride assurance and saved time, I guess it is value for money. I think I really need to bite the bullet on this.
But to be sure, I ought to shop around just a little bit.
( The front springs have 11 leaves and back have 10. The width of each is 44.45mm and the thickness of material is about 6.76mm (though these dimensions may be affected by corrosion, obviously).