friend of mine says do not buy upvc doors "off the shelf" as they are difficult to fit properly , he says i need made to measure upvc doors -is he righyt?
We bought a upvc door off the shelf from Wickes, and my Husband and Father in Law fitted it. Our house has been affected by subsidence and is on the tilt, so everything leans one way. They used packing to get it to fit right, and it looks great, although they are both qualified carpenters, so they are used to hanging doors and I think this helped.
With a slightly oversize solid wood door, you can shave quite a bit off all four sides to get a good fit. You can't do that with upvc. The only way would be to get a smaller size door, and build up the surround so's the new door would fit. Easier and better to get made-to-measure if you're sticking to upvc.