I must admit I had my services carried out by the dealer while mine was under warranty. I now use my long-term independent - he provides the filter, I give him 4 litres of oil, then I have a bit left over in case of topping up, which hasn't been needed.
My TA 85 is specced for 5W 40. I've been using Petronus Syntium 3000AV, which is the correct type with the all important C3 rating. Euro Car Parts sell it for about £20. I know that some folks here buy their filters from Shop4parts, but I haven't tried them yet.