This might be a silly question, but do full surveys for a house purchase check the central heating system and electrics or is it more to do with just the structure of the house etc?

I think we were offered 3 levels of survey when we bought our house - the basic valuation report, a homebuyers survey and a full structural survey.
We took the middle option which included checks for damp, building structure (ie any signs of subsidence, cracks etc), and made lots of general statements about the state of the house but didn't go into detail about the electrics, gas, central heating etc other than to say that it had them - it just recommended we got them checked by an expert!