Get this estimate from a plumber - my location is Outer London, which fact may make a difference.
================================================================= Estimate
Drain down and remove existing cold water tank. (Tank distorted) Supply and fit replacement 50 gallon cold water tank (site tank on existing platform). Connect to existing outlets and cold main.
Price : £514 + VAT (Labour and materials) ==================================================================
Comments gratefully received by an elderly (?) man, for whom £600 represents in excess of three week's state pension, and wonders if this is a rip-off. Thinking of trying to do it myself, but I (or SWMBO will not))cannot permit no water supply for more than a day, and I would have to buy relevent tools anyway. I know how to do it, but...
Thanks in advance
GOG