The LP12/Basik combination works well together and by most listener's standards would offer somewhat better sound than the P3. I dare say the current P3 does somethings as well if not better than an older LP12. Certainly in the ability to plug and play, the Rega is the far superior table. How much you wish to deal with the LP12's need for critical set up would be a question I would ask. Plus the LP12 seems to have run its course in terms of upgrades. Beginning with the tonearm you are considering, and assuming the table you'll find with a Basik arm probably isn't going to be a top flight, decked out unit, you would still have a long way to go before you hit the wall with the LP12. However, designs such as the VPI's are still at a point of ever upward momentum and might offer more potential.

If you are in London, the value of the dollar is in your favor. However, buying homegrown is probably better than a VPI at that point.