Christian McArdle wrote:
Okay, I'm thinking of uPVC frames, casement windows with the 2 side
parts of the bay having top openers and side openers for the bottom
part and I want it fitted.

Well my parents had a HUGE bay done in quality hardwood (may have
been oak, not sure). Each window was an opening sash. They were
double glazed, draughtproofed and factory coated in acrylic. They
came with a 100 year guarantee. Cost was around 3000 quid fitted very
professionally. Your original quote seems very high unless they were
factoring in structural repairs to the bay.

BTW, you may find that the window frames are structural. Replacement
with uPVC may result in collapse.

Christian.

How true. My local supplier told me he once saw some Anglian fitters take
out a whole downstairs bay without support.
The householder, who had just come home to see how they were getting on, was
less than happy when the upstairs bay etc collapsed onto his BMW. The repair
costs for the house alone were £30k