I'd say Squires too, they have Xacto #11 (which are the ones that come with the
GW hobby knife, and thus, for me the ones im most used to and use most) at a box of 100 for £15, which is brilliant
Infact, with squires, you have literally nearly anything you could want/need for the hobby, except the models
They also sell a TON of different plasticard, from plain (
iirc) to embossed)