Some contacts I have in the boatbuilding business reckon these are the best. I have had Tecsew sprayhoods on three boats and so can also recommend them from personal experience.
Look here:http://www.tecsew.co.uk/
No connection!
Where is your boat based?
It is always best to deal locally so you can meet the maker and discuss what you want. They can fit it and if there are any problems they are usually more easily resolved.
I bought mine from the same manufacturer as the original. He knew the measurements and the date when he made the first one in 1994.
I think that one can call this a good service (and it was considerably cheaper than by the local guys in the Solent)