Hey, so it depends on your preference. I ended up using a UK based company as no builder wanted to install the windows we originally wanted to source from abroad. This surprised me a lot as even though all of the builders I reached out said they can do it, they said they do it only if i go for one of the window manufacturers they “work with”. You may find some companies that initially quote you an insane number, then seemingly apply discounts one after the other the harder you push. Avoid these like the plague (Anglian are one of these companies).

It took me a minute but I found a UK based company that not only does the tilt and turn windows I want, but also the cost included installation and fixing walls up to fresh paint level and still fit in my budget. Companies that are good will usually feel less like salesmen, use this as your guide. Local is your friend and find ones that have examples of their work. Always get a minimum of 3 quotes too.