OK, yes; I bought them in bulk last time 
Also I have 10 quarts of oil in mine, at £6 each, plus 3-4 more used up during the service interval.
We do 25 hour oil changes and 50 hour filter changes. The O200 in both the Bolkow 208 and Jodel DR1050 have the filter fitted without the need for hoses.
I am surprised no one has mentioned the B&C products, very well engineered oil filter adaptors that are especially good for Lycoming engines with little firewall clearance.
