that hedge needs a good trim.

Thanks for the steer Margolada,

So, when I looked in a little more detail into the costs vs income (feed-in tariffs, etc) I realise that the sums involved will not work out in my interest, over the suggested 25 year period for calculating such things. The neccessary money invested now at just 2.5% over 25 years - or spent now on some other aspect of energy-saving home improvement (new gas boiler, new radiator vlaves, better loft insulation, and so on) - is likely to prove a better return on the money.

By the way, these local folks, the Victorian Terrace Energy Reduction Initiative (http://www.victeri.co.uk/) came round and provided me with a very useful energy survey, which helped clarify thoughts on all this.