Sorry a bit late to this discussion;
I used Jones Springs to make two new single leaves for my Ace spring assemblies. These were the leaves that have the 'eyes' at each end and I specified them with a shorter eye to eye dimension to introduce some negative camber.
The price was reasonable, and the service was very good considering that it was a relatively small job, plus they have original drawing for Ace and Aceca springs.
The problem was the eyes weren't truly circular enough to press in the brass bush the Ace uses. It would have been fine for a rubber bush. I ended up using a die grinder to polish the spring round. I thought this had worked ok, but after 500 miles one of the rears has developed some play.
My recommendation is therefore to remind whoever makes your springs that they need to accept a brass bush, not the more typical rubber bush and hence a bit more accuracy is required.