-
To add insult to injury they're suggesting to replace 10 radiators (!) so it's £3k after the BUS grant for us. Maybe just get a combi (when the boiler breaks in a few years) and let the next owners handle it in a few years?
This sounds more hassle and money than you'll be saving. Get a decent new combi and some smart controls, and leave the rest to someone else to worry about.
The combi quote from BG (yuck) came in at £4,300 for a 30kW Vaillant 830 (rear flue requirement limits us to Vaillant apparently?) and in the meantime I learnt that we don't need to cap off gas (as long as it's not used for heating) and can keep the gas-hob range cooker. So all in all the costs would be about the same (£3k + £300 for planning + £500-900 for structural eng stuff + chimney block) of course we'd need to repaint some walls where the new radiators are shorter and thicker.
The loft insulation top-up doesn't seem to be in the requirements list, granted it's a good thing to do and we should do it anyway and we will, but nice that we're not held up to that before the works can go forward.
This sounds more hassle and money than you'll be saving. Get a decent new combi and some smart controls, and leave the rest to someone else to worry about.