Latest quote came in £11,940, very sparse on details, nothing on warranty etc. but they did list the panels, inverter & batteries,
12 x PLM-400OM2B-66 400 Watt Panels (Perlight Solar)
1 x H1-3.7 (Fox Ess)
2 x HV2600 (Fox Ess)
Quick look online panels £200ea, inverter £1300ea, batteries £1000ea, chuck in another £1500 for misc/scaffold thats £7200 what makes up the other £4700?
Simply put, he may be profiteering - we all have to remember that the demand is high so that is pushing prices up not down. As above, my preferred installer is booked for the next 10 months so why would they charge less?
Having said that, with all professional installs, you are paying them for their experience, qualifications and knowledge. This will include the electrical aspects which are not a DIY job and also the commissioning of the system with whatever paperwork is needed. Some manufacturers will also insist on "professional install" to validate warranty so that is a consideration.
My electrician charges me £30+VAT per hour - he is excellent and his RPH reflects not just his labour cost but workmanship plus insurances, transport, accountancy and all other business running costs so yes, face value is higher but it's reflective of their running costs and for them to earn reasonable living.
When it comes to components, it's not unusual for any professional installer to add a 10% mark up on the items sold, if not more.
I'm guessing but let's say it takes half a day to design the install and order the relevant kit plus two men, two days to put up the solar panels then that's £1,300 then your electrician at say £700 including materials etc. then the headline profit is not quite as big.
The only thing you can do is discuss with them to get a better breakdown of costs?