Yes you can just order the 10w60 stuff through Halfords website and either deliver or pick up from the store next day usually. Its the cheapest I've found and being in stock. Its' the Castrol EDGE M stuff.
I might get the micro filter changed as well, but just wondered if it "needs" changing every time as suggested.
Yes most indy use the autologic system which can apply all the updates just like the dealer, but they're usually reluctant to do so in case they fry the ECU.