This is a short list of a few places of interest. This is not exhaustive, and never will be. However if you know of a worthy or trusted addition please suggest it through the Contact page. Links are in the order of typing, and only that, no specific preference or endorsement intended.
Kirkbride Airfield / Solway Light Avaition
http://kirkbrideairfield.weebly.com
The British Model Flying Association represent model flying a in the UK. They manage clubs and arrange insurance for almost all model fliers. You are well advised to follow this route either through finding and joining an affiliated club or independent membership. CDMAC is a BMFA affiliated club.
The Large Model Association, Thinking of a model over 20KG, then you will need to speak to these people, really, its the law.
http://www.largemodelassociation.com/
Local model shop. Both RC and non-RC models supplies.
http://www.jacksonsmodels.co.uk/
for anything electric
limited website, limited stock, best for helicopters and cars - shop is on London Rd
Radio Control Models, Planes, Helicopters, Cars, Boats, Toys, Hobbies and Kits
http://www.rcmodelcentre.co.uk/
Full service model shop with great range and some excellent prices, the best stocked model shop I have physically visited.
Another well known large model shop
Another well known large model shop
http://www.sussex-model-centre.co.uk/
range of materials, parts and accessories, including aircraft kits and manufacturing and laser cutting services
http://www.slecuk.com/slec-online-shop.html
Mostly cars, but not all bad
mentioned only as they are a UK company manufacturing jet engines
Good UK RC flying magazine, website has good forum, lots of articles and aircraft plans.
model shop with interesting range of own aircraft kits
http://www.galaxymodels.co.uk/
for product details and information, you'll have to buy through a model shop.
only a few of the many brands that each distribute are listed
Many models, engines and every accessory known, Futaba Radios
Spektrum Radios, Hanger 9 Kits, EFlite models and many more.
http://www.horizonhobby.co.uk/
Various Models, batteries, motors... all sorts.
http://www.jperkinsdistribution.co.uk/