Just to follow up, I found an electrician who is the neighbour of a friend. I created a list and he ordered it from the wholesalers. Interesting to see the trade price as we were putting the order together in his office; some items were much cheaper than what you see in Bauhaus/Coop/etc - other things were pretty much the same price. Examples (after adding his margin) - M25 flexible conduit - half price. Combined RCD/MCB, 16A, 30mA (Hager) - same price as Coop. 1.5mm˛ installation cables - same price as Coop. Switches and sockets - half price.
A lot of people claim that Coop/Bauhaus only sell cheap rubbish (as is very often seen on www.haus-forum.ch
) - codswallop. I wouldn't call Feller, ABB or Hager cheap rubbish by any stretch of the imagination..