Don't, what ever you do, get in one of the big companies. Right sharks. Get quotes from a local company. We had three companies round, the big company rep wouldn't leave, was at out house nearly two hours. Their 'initial' price was four times the local company, but if we signed there and then, we could have it for only twice the price of the local business. Had to kick him out of the house in the end.
The local company literally measured up and left. Dropped off a quote a couple of days later. We went with them. We still call them back now if we need anything doing - right on lockdown last year one of the kitchen windows smashed for no reason. As soon as they could, they came out and took the window pane out to re-use the plastic 'bar' on the inside - back within an hour with a new pane.