[TG] [TG11] i50 depth (new) lighting issues

[Draughty]

Hi,
I recently purchased and installed a new i50 depth; S/N 0290060; Software 1.06.
It is a stand alone installation.(except it shares power supply; see below)
The manual says there should be 9 levels of back lighting but there are only 3; 1 is too dim to see from just about anywhere while 2 is much brighter than necessary and detrimental to night vision: how do I see the 9 levels?
Also if I switch off at the circuit breaker/switch the lighting defaults back to level 1 from the level 2 that I have set.
If I switch off at the instrument it keeps what I have set, but that is inconvenient as I wish to switch it on and off with the wind and speed instruments it shares power supply with.

I have done a reset to factory defaults and checked that it is set as a data master.
The depth units I have set and the offset are kept when switched off at the C/B, what gives with the lighting?

Thanks