You can get universal ones very easy, most are a very similar resistance, anyone really that supplies/maps ecu's will no doubt have these, I refuse to pay cossie tax if I don't have to.
I got mine from Dave Walker@ emerald, as we were mapping it at the time it went duff.
The beauty is if I ever need another the set up is simply connect then 2 mins on the laptop to scale it to the ecu job done.
tabetha