I'm moving into a new home that has an old boiler, the label on it
says "Thorn EMI Heating Limited M56/76 & M80/100 gas boilers". There
is a cylinder above it in the bedroom and in the attic there is a cold-
water cistern and a feed-and-expansion cistern. I'm after some general
advice (be gentle on my I am totally ignorant re central heating/water
systems!):

1. The timer on the system is not working - could I fit a modern
thermostat and timer to the boiler?
2. Alternatively, if the boiler is replaced would I need to replace
all the radiators as well? Is there a difference between modern
pipework and older (possibly over 20 years old) pipework diameter?
3. Can the cylinder be moved into the attic? What affect would this
have on the water cisterns already in the attic?
4. If I replace the boiler, what should I replace it with? I think a
combi would be out of the question as the house is a large 5-
bedroomed, with a couple of bathrooms.

Thanks very much