I went to Kaizer Motors 2 days ago and asked him about costs. From memory this is what he said about my 04 350z.
P1 (oil change): £87 or close to
P2 (oil change + oil filter?): £150
P3 (oil change, oil filter, air filter, brake fluid and inspection): £220
Believe he also uses Mobil 1 as well.
He also does any diagnostics for free. I mentioned a possible faulty gauge to him and he immediately said he'd do it for free.
He is in Rochester, Kent. To anyone local, it's near Kingsnorth power station and is on a fairly new estate. Google images will show you