Combi Boiler - does this mean you can do away with hot water cylinder?

[deepest]

And how difficult is it to move the position of the boiler - have an old one in kitchen - on external wall but want to replace it move this a few feet along....

Yes.

Usually not a problem to move. Though obviously needs to be done by a suitably qualified person. My parents moved theirs (and upgraded to a combi) for 650. They purchased the boiler themselves, and it was moved alot further than a few feet.

The fitter will put it wherever you want (as long as it is practical). We moved ours upstairs (external wall) at no extra cost.

yes. But that is not always a good thing. How many people, baths and showers are in your house? Fill a bucket at the kitchen sink cold tap, or the garden tap, time it, calculate how many litres per minute you get.

it needs a gas-safe engineer to move a boiler.
For a few feet most people would have it done when they buy a new boiler, not as a separate job to move an old one. Remember to put it in a place which is close to an internal drain, e.g. a kitchen or bathroom waste pipe, and where the huge steam plume in winter will not blow past a window or disfigure the front of your house.

thanks all - really helpful - we will buy a new one - it is for a small 2 bed bungalow.