Thanks for taking the time to post your first deal @muddyboy :3
Same price in tesco Beckton
Works great on my 1 series. STP also works well
Not used this but I find miller's equivalent works well, better pickup at lower revs, smoother running and cold starts. Reverts back to normal when I don't use it but I think it keeps things clean if you use it every so often.
Costco, from Monday, are selling 4*500ml packs for £12.58. £1.57 per 250ml.