Jon Wild
if you think the problem is getting worse after the central heating was put in, you need to look for damage to the joists (is the ceiling below cracking?) if it is an old problem that you have just noticed don't worry about it. Levelng a floor is a big job and not worth the bother unless there is an under-lying structural problem but if you do want to do it you would need to get all the old floor up and lay level joists next to the bent one and re-floor. Floors and ceilings in London are old and wobbly I have seen differences of up to 80mm
