All the parts are easily available from the usual stockists.
ClickySome are cheap as chips and some will cost the earth.
One thing I have noticed, the car shown in the picture has heated seats which wasn't an option on the Lotus.
The only thing I could advise is to put them in the same position as the M200 for authenticity or see
Here for the Vauxhall switches. (Not red, but White)
I'd also recommend changing the dash wiring loom as oppossed to replacing every connector and pin (One plug against loads)
I hope your project goes well, here's looking forward to seeing some more pictures.
TTFN
If you have a problem, if no one else can help, and if you can find them, maybe you can hire... The N/A-Team.