I am based in the UK and have managed to track down the following list of suppliers.
I have succesfully ordered items from each of these suppliers in the past but their inclusion in the list doesn't hold me to any personal guarantee regarding quality of service. ie don't direct any moans to me!!
This is by no means an exhaustive list - and I may not cover all of the products they sell.
Suppliers: if you want me to remove you from, or add you to, the list or you feel I have mis-represented you then let me know. Please note this page may disappear eventually. So if you are interested in paid advertising then get in touch.
In purely alphabetical order:-
Motor controllers, sensors, wheels, motors, microcontrollers, platforms and chassis
All things nautical - plus R/C. Also good for servos.
Source of "all things plastic" - so good for HDP which is great for easy chassis construction
Large company - good for components
All sorts of R/C stuff - mainly aircraft. Also good for servos.
Good for components
Humanoid robot kits ($$$$). Website isn't too friendly and can break into Japanese sometimes. But if you persist then they are also a SparkFun distributor. So save on all that postage, delay andun-welcome demands for customs import duties when your order arrives!
Sensors, Cameras, Motor/Servo Controllers, LCD displays, Servos
Components, sensors, Motor/Servo Controllers, Motors/Servos, Mechanical (bearings, pulleys, hubs etc)