You've just reminded me of a cold call I got from Everest when I lived in a flat. They were selling conservatories. When I pointed out I lived in a first floor purpose built flat her response was "We can fit them to any type of building. How about get one of our agents round to measure up ?"...
I'd be very careful of Anglian. I had them quote for one of my old houses - all very sales and pushy. They measure up and then come out with the list price. They then go through a ridiculous piece of theatre to give you discounts - 'oh look, there's a postbox opposite your house so if you allow...