@david1972 If you can get under the car enough it's easy.
@Sirspidey you can find a cosworth panel filter on eBay mate.
5W 40 usually use mobil but just whacked in some castrol edge titanium for a change.
I change my oil every sub 1000 miles. Even more relevant if you run higher bhp, as Tidgy says it surprising how quick it gets manky. I pay £65 for an oil and filter change so don't really worry about it to keep it tip top. But saying that it takes 3 months to do the milage. At the moment I have a hks filter but would normally have Subaru.