A replacement pressure switch (all I *actually* need is the spring contacts) for my Jabsco pump is more than £30. All their spares are silly prices, even paper gaskets cost tens of pounds.
So, as I said, I'm looking for alternatives. The difficult part is finding a pump that doesn't deliver *too much* pressure. It's easy to find pumps that deliver 60 to 100 psi but this is too much for the bendy plastic pipe plumbing. I need a pump that delivers around 10 to 15 litres/minute at 15 to 25 psi (that's 1 to 1.5 Bar).
As I said it's easy to find pumps that deliver 60psi or more and cost only £10 to £15 but all the lower pressure ones cost £60 or more. Maybe I'll have to spend that much but I'd prefer not to (surprise!).
Alternatively a pressure switch that operates in the 1 to 2 Bar range would solve my problem, I could use it with the existing pump (and a big fat automative relay to handle the current if necessary).