[member=175813]Maysie[/member] , Check out RHI (Renewable Heat Incentive). It's not dependent on any other benefits.
There are two classes - domestic and commercial. The commercial one pays you based on the heat you produce (it's measured), whilst the domestic one pays a grant based on the size of boiler you have installed. This is governed by the size calculated by an energy assessor. This money is paid to you quarterly for seven years, and then you're on your own.
At its most basic, you have to shell out the cash for the installation yourself, but then the payments also come to you. However, there are also financing schemes like Landroverroy's, whereby you don't buy the boiler yourself, but then neither do you get the payments.
Beware, there is lots of skullduggery afoot in how these systems are calculated and sold. According to the companies we dealt with, we stood to gain about 3x the cost of the boiler back over 7 years when compared with our existing system. When I looked at those claims critically, as a qualified engineer, I found them to be total rubbish. The reality was something nearer to "The running costs for the new system will be almost the same as for your old system. You spend £X on a boiler, and over seven years, you'll get back the same amount from the government. Basically you get the boiler for free."
The amount of the RHI payments has decreased since then, making it less attractive. However, if you're going to be getting a new boiler ANYWAY, definitely think about getting one that qualifies for RHI, since it will still cover the extra cost of pellets etc, when compared with for instance a new oil boiler.