Stupidvprices for what they are

I'd wonder if you could solder a green LED in place of it, though you'd have to drop the voltage to avoid blowing it. You might also have to play around to get the right level of brightness. That price seems to be one of the cheapest around though for the green ones.

Maybe buy another switch to raid the bulbs from instead?

Here you go, replacement switch complete with bulbs, https://www.ebay.co.uk/itm/RANGE-ROVER-P38-MKII-Cruise-Control-Switch-Dashboard-94-To-02/333579015798, or https://www.ebay.co.uk/itm/RANGE-ROVER-P38-Cruise-Control-Switch-Dash-Surround-94-To-02/303490972259 or if you want to be sure they work, brand now old stock https://www.ebay.co.uk/itm/AMR4141-NEW-RANGE-ROVER-P38-CRUISE-CONTROL-SWITCH-UP-TO-WA410481/112960341590.