Hi Pete, welcome to the fold!
Join the NPS (a measley £10, well worth it) and they'll send you a mag with lots of sets for sale in the back.

Useful links:
http://www.northumbrianpipers.org.uk/
http://www.nspipes.co.uk/

Makers' sites:
http://www.nspipes.co.uk/nsp/ww5make.htm
http://www.evansweb.co.uk/
http://www.burleighsmallpipes.com