For baking accessories: Bakery Bits is tops; http://bakerybits.co.uk/
I buy my Panettone cases from here as well as the Panettone essence so essential to making this loaf. Also the Bannetons for sourdough are good; pricey but last forever.
For advice on baking, videos of techniques etc
http://www.weekendbakery.com/ is very good. Although American, it has a lot of hints and tips, plenty of videos and is well worth a look;
http://www.sustainweb.org/realbread/; doing a lot to promote better bread and has lots of advice;
http://www.virtuousbread.com/how-to-make-bread/ is a great idea, teaching people to bake bread and then starting a community micro-bakery;