There are more firms offering good quality throwing knives, though some of these firms are smaller companies and based in the US. Below are a few makers that are obtainable in the UK.
Branton Knives
US Heavy weights.
Will ship to Europe for around US$ 15 for first blade.
Check out his site by clicking the image.
Cold Steel
Fantastic quality for the price.
For throwing by blade or handle with great penetration.
3 Sizes: 10, 12, 14"
Made of Carbon V, this lot will handle loads of abuse.
These can be purchased in the UK from Framar Knives - great service and quick turn around.