We're just after having an Apeer Composite door installed by Regency Windows. We're very happy with it and Philip from Regency was sound to deal with. They were second cheapest of all the quotes we got. The guy that came to install was quick and very tidy and finished everything off very well, nice neat seal around the frame and good saddle etc.
I wouldn't bother going to Senator, they quoted us a price over three times more expensive than what we ended up paying!!!
No affiliation to Regency by the way, just a satisfied customer.