For anyone interested, got some prices back:
Heater panel (not cig lighter type) - £35
2x Electric Windows - £10
2x Single Buttons (Heated Screen etc) - £8
Headlight Adjuster - £4
Return Delivery - £7
Total £64
Call it £60 all in.
For that price I'm tempted to just pick up my tools from where I used to work and do it myself. :?