Either, they both support Dave, and the reason I recommend them is because they're decent products at a decent price, and the rest of the TT stuff is awesome. However...
The Viz hubs on T-UK and Tarty are identical, both screw on, so you just need a 12t sprocket, from http://www.tartybikes.co.uk/product.php?pr...;category_id=73 (1st option, £12) and you can screw it right onto here... http://www.tartybikes.co.uk/product.php?pr...;category_id=62
The reason I recommend the Viz is because they're pretty decent hubs and lightish too. Then again anything with sealed bearings and a decent set of allen bolts and you're sorted, even the Onza hub http://www.tartybikes.co.uk/product.php?pr...;category_id=62 is good, and light!
I'd advise you go for a 32h hub too, just because you'll have more choice of rims in the long run, I've got 36h on mine and it means I'm stuck to only 2 or 3 rims