Black tape on the cluster. It's the obvious solution.
Apart from the tester realising something is amiss when his eyes are streaming.
Dodgy earth or chafed wire? Could you have dislodged the cam sensor wiring whilst working on the EGR?
Doubt it as the two are either end of the engine but I'll go out later and remove the TB cover and just check the cam sensor wiring and fixing bolts .
I'm sceptical that both have failed for no apparent reason . I've went through the wiring diagram and they are off separate circuits from the ECU with no apparent external connection .
I did examine the cam sensor wiring but it was OK.
Last drove it about three weeks ago and it was fine then .
Not sure what voltage should be at the egr valve when static or running but zero volts when static with ignition on .
I last changed the cam sensor in 2016 but it's done very few miles since .
I'll try and get to the OBD diagnostic set tomorrow AM and see what clearing the fault codes does .
Failing that I'll walk away from it until I get another chance to look at it ,more serious problems to deal with at present .
Thanks for the suggestions .