Retrofit project planning starting with underfloor insulation

I still don’t have any final window and doors install costs as the manufacturers separate these as well. I also got one for Norrsken, who’s windows were about the same as 21 degrees but they estimated an installation price to be around £5000 plus £1000 for an initial survey and £550 for silicon (Everbuild 825 Mastic). I need to clarify which windows are included for this as I had the quote for several options and asked for bay window panel pricing as well and maybe they have included that for the estimate. This installation cost seems a bit excessive for 2 windows and 3 doors on the ground floor.

Does anybody have a more general idea of install costs? How much per day for a decent installer team of maybe 2? @Tim_Gilbert I was originally thinking this shouldn’t be more than £2-3000 and would take perhaps 2-3 days as it includes a wider balcony door as well.