if OCUK is still at Unit 40 Imex Business Park - Fenton - Stoke-on-Trent then ill give you a small tip, most GPS's wont take you to the right place (because its a industrial estate), its just round the corner from were the GPS takes you, there is a sign or two for the Imex business park just off the main(ish) road. if you find the sign that will take you straight to it.
the building your looking for is a big one (gray zig-zaggy metal) with the road going straight through the middle of it.
As for pick ups i know you can buy stuff direct there and i have never had a problem with them being out of stock, i guess if you check the website before you leave that will give you a good idea, but im not sure i you can pick up online orders or not.
can i ask apart from time saving why are you driving from london to stoke and back? surly it works out more expensive then the £10 delievery?