"David" wrote
| Firstly, the flat has an immersion water heater and a rather large
| cold water tank ...a bit of extra storage space by removing the cold
| water tank.

You can get a mains pressure water storage cylinder but AFAIK they're
supposed to be installed only by plumbers certified to work on them. If you
have a very small flat heatbanks and the like probably are not a realistic
option.

| Secondly, is an immersion heater the best way to provide hot water in
| an electric only flat? Are there any new and exciting tecnologies that
| could be worth looking at? I don't mind starting from scratch as the
| flat is so small and there is not central heating.

An electric immersion heater is for most intents and purposes 100%
efficient.

| Finally, and on a different tack altogether. The flat is fitted with
| electric ceiling heating, ... it is fairly common around Woking and
| Guildford.

Oooh. Is this an ex-council flat from the 1940s by any chance? The name
Dulrae is floating into my mind ...

Electricity is about the most costly form of power there is, so you might
want to consider:

1. Ensuring your HW cylinder is well insulated (preferably a factory foamed
one) and use off-peak electricity (Economy 7)
2. Installing a night storage heater(s) and use off-peak electricity - but
these can be a bit bulky.

An alternative could be to remove the hot water cylinder altogether and use
an instantaneous electric shower together with an under-sink storage water
heater for the kitchen. Especially if the kitchen backs onto the bath and
you are the only occupant of the flat, one under-sink should do both kitchen
sink and handbasin. It would *not* fill a bath in a reasonable time, so you
might replace the bath with a shower tray and use the space gained to
perhaps move a washing mc and tumble (stacked) into the shower room (subject
to shower room zoning requirements under IEE Regs of course). And some
people consider electric instant showers to be Worse Than Bleeding Useless.

It would cost nothing to enquire how much it would cost to install a gas
supply, if it is at all possible, and what the market value of the flat
would be with full gas ch and hot water - might actually be worthwhile in
the longer term.

Owain