For the U.K. your best bet is a chap called Roland.
He's very helpful and his work is top notch:
www.facebook.com
You'll need to send your buttons/units to him.
He's very helpful and his work is top notch:

Sticky Plastics
We specialise in refinishing sticky buttons and plastics in car interiors. Experts in Ferrari &... Castle Eden, UK
You'll need to send your buttons/units to him.