Builder wanted to add dormer windows + velux rooflights to attic

[Naiada]

Can anyone recommend a good, reliable and reasonably priced builder for work to our attic which will involve installing both Dorma windows and Velux rooflights, plus minor internal alterations. It's for a 2nd floor flat with a steep pitched roof. We want someone who has a good track record of similar work in the area, and excellent references.