OK. Have removed part. Turned out it had been removed before; that's why it was a pain to extricate, because the front clip was all mangled. Plus, the side clip as appears in some parts photos was not on our switch.
rsgaz: I think the module you link to is not a stand-alone part. It would appear from mine that you have to dissassemble the module in order to attach it to the fascia plate, not just take the assembled module and screw it to the fascia plate
Also, the part number on mine does not match the part number given to me by Mitsubishi. The part number on the side of mine is: MR773327. Put that in ebay and it comes up with a similar module but in LH drive format.
I have an idea the module part of the assembly has a different part number depending on number of switches and whether it is L or RHD and the complete unit has another number, not marked on it that denotes the whole assembly.
Price-wise, the cheapest thing to do would be to buy the 4-window switch with a blue facia. Having seen how fragile the interior of the switch is, I'm not sure I want to pull a good working one apart.
Otherwise, I could buy the dearer Carisma switch which is correct in colour and number of switches (it's even RHD) but has a different shaped end, which is no bother. Just need to check to make sure (I'm confident it will be) it is the same size.