mimififi - why not try www.suttons-seeds.co.uk ?
They and Dobies are now part of the same organisation and they offer a very effective on-line service which I have used for buying soft fruit bushes. You can probably also order a paper catalogue fvia the "Contact Us" facility on their website which will tell you the best varieties available.
And don't forget to plant a thornless blackberry. They crop very prolifically (far more than raspberries and loganberries) and they freeze beautifully. If you plant one established blackcurrant and redcurrant bush, you can easily strike cuttings from them by sticking cut stems in moist compost and get subsequent plants for free (if you're patient).
Suttons gave me a very good service. When one plant I ordered looked a little sickly after several months it was immediately replaced without question.
Happy planting !