Hey thanks guys!
I've checked the caps on psu in case they weren't smoothing and causing trouble. They all check ok. (replaced)
The country and system settings are correct. Also factory reset in service menu.
I asked if the problem started after the March retune....no.
I'm liking the sound of the smd caps around the tuner. I'll try those later in the day and keep you posted.
Incidently the pcb is a 17MB25-1. With specific version spec for this set.
Thanks again.

Geoff