Not necessarily inexpensive, but have you tried Team Blitz?
Here are a few I found online...
https://www.ebay.com/itm/MK1-C...83.l4275.c1#viTabs_0
Might also try ebay UK.
http://www.oldpartstore.net/sh...ire-07-70-08-73.html
Note that I have not confirmed if these are the right parts to replace your switch.