Drayton SCR and RF1 set up?

I seem to be suffering the same difficulties as others with random functionality of the heating.

Can some one confirm the set up is free from other radio interference such as kids toys, wi fi or suggest any other sources of radio interference I may need to eliminate?

if as I suspected, having played heating engineer tennis over last few months, the problem is the SCR as described and there is a repair as per Dave Cardiff description can anyone confirm it works and if the repair is an enhamcement of the orignal design or a like for like component replace ment ? Thanks and a bit cold