I bought the bag of Lewmar "Barient" springs referenced by Bill at WM... lifetime supply. a couple of years ago ...

Also have used the Aussie company for replacement parts on a Barient Self Tailer ... Didn't have a problem, but then it was just a couple of light weight plastic rings for the self t part. That company works email, and didn't seem to make much difference that they were that far away except it did take an extra week.