Firstly, if you are running out of heat during the evening, check to see if your supplier offers economy 10, they may not advertise it, but that doesn't mean they don't offer it. E10 gives you cheap rates at (roughly) Midnight - 5AM, 1PM-4PM and 8PM-10PM allowing you to top up just before you get back from work and before you go to bed.
I hate to say it, but please ignore anyone who tells you outright to dismiss electric heating. Yes it will be more expensive per kw of heat output, but you do have to factor in the installation costs, the yearly servicing costs, the repair work from having the system installed and the systems estimated lifetime.
A standard central heating system installed from scratch is going to be upwards of £3k. A well insulated house (>270mm loft insulation, cavity wall insulation etc) will easily get by with a 400w panel heater in each room (perhaps 2 in the main rooms) and at £30 each for a
slimline panel heater, you are looking at a standard house costing about £300-£420 for the heaters plus a days work to swop them for the storage heaters. Saving you about 2 grand initially.
Servicing costs for electric heaters are non-existant and there's almost nothing that can go wrong with them when installed correctly. Even at peaktime E10 rates (18p/unit
) each one only costs about 7p per hour and at off-peak E10 rates (8p/unit) only about 3p per hour.
It's definitely worth doing the maths and seeing which works out better for you, but I've got the panel heaters linked to above and I find they do a lovely job of heating the house without the expense and loss of space associated with central heating.