Dinghy Wear

Personally I advise anyone new to the sport to check out Decathlon. For about £100/£150 you can get good quality kit that will last long enough for you to figure out if you're hooked on the sport and want to splash out on more expensive stuff.

Get a wetsuit (Long johns are more popular these days because they let your arms move better but it's personal preference, most important part is that it fits properly), spray top, long sleeved rash vest, gloves and a buoyancy aid to start with and add a hat, thermal rashvest and salopettes in the autumn.

Which bit of coast? South Devon or North Hebrides would effect your clothing choice.
Many people make the annual pilgrimage to the Dinghy show in march and try stuff on there.
Unless you have a good shop nearby it is online only these days,
but
The likes of Rooster and Wetsuit Outlet offer free delivery and good returns policies.
I have returned wrong size items to both without issue but I did have to pay the return postage.

Smashing Gents(?). Loads to go on. As someone else stated, not too many shops to buy your gear from, do most people buy on line? the only Gripe I have with that is its going to cost about 10 quid extra, (if you send something back) and even though I will be buying pretty soon, there not 'that' cheap!!

it depends where you are going to be sailing, I used to sail on ponds and lakes with jetty and so t shirt ns shorts were fine, I now sail off a beach, up north and my default clothing is dry suit, the middle ground would be longjohn and spray top as above, dont forget gloves -  half fingered Gill gloves are fine, unless you have cold hands routinely, in which case neoprene might be best - crewsaver phase2

Many thanks gentlemen. Something to go on now.
tks
Terry