Thank you all for your advice and suggestions. Really helpful stuff. I have done a lot of reading on here and have already made some investments. I have the Hobbywing 860 dual motor ESC from Modelsport, although the motor wires were too short to reach so I cut off the connectors and extended them with the stock Tamiya ESC wires with these - (which are excellent btw)
https://www.amazon.co.uk/gp/product/B0716GK2F2/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1
3s Lipo - done
Ballracers from RCbearings - done
Servo horn - I’m not sure what this is. Is this to have dual servos front/back?
Motors - I went with Tamiya Torque Tuned Motors - are these ok?
Shocks - still to get, although I’m struggling to find the Traxxas T-Mass shocks for less than about £85
Metal anti-rotation brackets - found these on eBay https://www.ebay.co.uk/itm/371928197237 - like them in black.
So far we’re up to page 18 of the manual - tyres to connect next