I have been using a Fireface 800 with a Mac for over 4 years of untroubled constant use, but I turned it on yesterday and one of the Headphone channels was missing (left side I think). The headphones work in a different amp so I have eliminated those from the equation. Everything else is the same as before the failure so I can only conclude it is a hardware issue :-(
I did check routing and the headphones output in totalmix is showing both channels working and the main outputs 1&2 are working normally.

Where in the UK is the best place to get it repaired?