Universal Joint (WST 01)  :

This is actually made by a company called Huco, part number 105.32.4242 £8+VAT , £25 minimum order (I bought a lifetime supply). This is the page listing UK distributors. On my machine the joint was held onto the joystick by two small grub screws, you have to drill and tap the holes for these yourself. I believe they were £25 from AVD.

Getting the old UJ off can be tricky though, it it splined onto the the joystick quite tightly and even with the grub screws removed you'll probably need a mallet to get it off. On my machine the other end appeared to have been glued on, this is believed to be a user modification by a previous owner but is is possible that they come like that from the factory. Either way it took rather ungraceful use of a hammer and chisel to get it off. My trike has carbon tubes, if yours doesn't then things may work a little differently.

Seat Suspension Rubbers (WSE 01) :

These are available form RS components, part number 360-2873 £2.07+VAT each made by Paulstra. Or at least I'm pretty sure that's what they are, my speedy never had any so I'll update this page when I actually get some. In the mean time I'm pretty sure these are them.