Range from the cheapest replacement of a header tank £161 (Mohammad Reza Mohammadi based in EN5) to the dearest replacement of a header tank £541 (Junior's Plumbing drainage & heating based in EN4).
Comparing plumbers estimates for replacing an expansion header water tank for your central heating gives you an idea of who will be better value but the best way to compare costs is to get actual quotes.
What to do - Get rates and quotes to replace a header tank in N20 by posting a job with HaMuch and we will send it to plumbers in N20.