Herbs in the UK?

I know, I know, Im being cheeky putting this here as its not directly related to Iodine but after Grz kind reposting of the their 'Green Drink' Ive been trying to hunt down good quality herbs in the UK, without much success.

Does anyone have any information as where to look for good quality organic herbs that arent really, really expensive?

I may see if iHerb in the US will post internationally...

The amount of spirulina Im going through at the moment means I'll be spending at least £20 a month on that alone (I get the All Seasons Health brand, its brilliant) and I just cant afford it. Maybe one really good herb is better than 3 or 4 weaker ones....?