I still don't inderstand why Pashley stopped making them - when I rang up and asked if they were still available just not on the website, I was told that they had problems with the plastic supplier and decided that they just didn't want to do them anymore.
The impression I got was there was no safety issue, merely it was too much hassle for too small a market - perhaps they don't have the storage to hold a stock of them. Given that 2nd hand ones in poor condition go for so much on
eBay, I'd have thought that Pashley could afford to do some small limited runs on seats and they would sell. But what do I know...