I only had 2 doors done, front and back door in the kitchen.
Also, my window project was combined with the garage conversion. The quote on the single windows project was something around £17k, I negotiated to £8k, and then I decided to leave my garage conversion with Anglian as well, they further discounted to £5k. Anglian only accepts the finance with GE for payment, so I lost £300 on interest of 28 notice period + administration fee on pay-off. The total cost was £5.3k on windows.
I don't have any issues with Anglian or their services, the only thing that is frustrating is Anglian doesn't accept the payment from the clients, even you are able to pay cash in full amount, you will still have to go with GE, which means you will lose at least 28 days interest even you pay off in day 1.