I've just been made aware of your website, and have a complaint about a company miss selling their services - it's you.
You're using massively out of date solar PV prices to produce your payback figures, which then unsurprisingly result in the payback figures being poor. We last sold a 4kW system for ÂŁ12,800 about 15 months ago, with the industries current prices being approximately ÂŁ7-8,000 fully installed.
The rest of your figures are similarly wrong, and I believe the EST have recognised this as they seem to have removed PV from their calculator entirely.
Also, panels cleaned 4 times a year? I doubt most of our customers have yet needed to have their panels cleaned once, so this is a load of rubish.
EPC - the vast majority of current band E properties will achieve a band D once a 3-4kW solar PV system has been installed anyway, so the figures for houses unlikely to achieve band D without any other works being carried out is more like 20-25%.
Also you've not updated you website information about the FIT cut which is now coming in August not July.
All in all, for a company that's complaining about the solar industry miss selling, you're doing a pretty shoddy job yourselves.
Take this as a warning to sort your act out before I and others make a complaint about your misleading sales tactics.