I bought a suit of sails from them about 8 years ago along with spray hood and dodgers - sails are still very good - spray hood has a few holes in it at points where it rubs on the frame and some of the stitching on the dodgers is in need of repair, I understand they have moved premises to Mithchells Boat yard -but I havent been there yet. They used to supply brill coffee.....
I haven't had any new sails made by them but they have carried out several repairs/modifications to my existing sails and they have always done a good job for a reasonable price and on time.
I'm also at the same point. Have talked with several sailmakers including Southern, and Kemp (Wareham). Of those I talked with Kemp seemed to take the greatest interest in what I wanted out of the sail and were the most proactive in terms of suggestions. Quotes from Southern and Kemps would be covered by a slightly stretchy £50 note (for a 250 sqft sail). So you might like to add Kemp to your shopping list, if you haven't talked to them already
Southern are good, Kemps though will inspect your sail at the end of the season and put wear patches, where genoa rubs against standing rigging free of Charge, as one of the of the above said . Kemps seem to be more interested in most and they will come to you if required.
I've had excellent service in the past from Kemp Sails. The cut was excellent too, almost racing quality in a cruising sail. I've seen ads for Honk Kong Sails in PBO of late and also there's a web site - www.sailsdirect.com which looks interesting. I'd be interested in any comments about these and other options.