@John Laidlaw and @daveenty are your men for this...
Cheers Dave - I was under the impression you had one! Make a note for future....I've never had one, preferring to use the bare minimum I can get away with for insurance, currently a Cat 6 tracker.
The other two name above have definitely owned them, with AMGeed still having one on the E63.
As far as the original question goes then no, the warranty will not be voided. This information is on their website I believe.
And I bet they never washed the signsSorry a bit late to see this!
No it does not void your warranty , you just have to warn them you’ve put it in ‘service’ mode when you book it in, that mode means they can move the car around the workshop but if they exceed 30mph and sustain it will not restart and you will have to interject.
I made up several laminated signs with this warning and also the ‘dont wash’ as well
Not even once !!And I bet they never washed the signs