The rear lights have been changed for UK use so the reverse and indicators are on the same bulb.  This maintains the three red tail lights.  Much neater than changing the outer red light to orange.

One of the rear bulbs was defective and would flicker rather than indicate.  So new bulbs and all is well, nice easy fix.

Also noticed that the front passenger side indicator was not working.  It was on while the parking lights were on, this would have been correct for US use. The people that did the UK modification clearly messed that one up. For UK use the light should only be used as an indicator.  Quick investigations showed the wires were connected incorrectly, a few replacement terminals and all is well.