Take your material with you, as the choice in the shops is a bit frantic and a lot of it is man made, so will make you sweat.
The dressmaker I use is very good, I have had dresses, trousers etc., shortened and also a lining added to a dress. I have not had anything made but last time I was in, a German lady had had a dress made and it was lovely. Just take a picture in of what you want and the ladies will copy it for you.
Directions:- Walk up the Main Street away from the bridge, keep right and walk right up to the traffic lights and turn right. Walk along there is a Barber Shop down a flight of stairs and next to it you will see a lot of dummies with dresses on them, just go down the flight of stairs after the dummies and you are in the dressmaker's she has a room for you to change, her selection of materials is in there too, but IMHO bring your own. She speaks some English and it is easy to explain things to her.