Plenty of good and competent places around, then there is DIY which is free apart from the parts needed - but for maintaining a service history, a dedicated third party garage, or in some cases even the agents if it's just a simple oil service to get the book stamped!
My E90 has a few months left, so want to maintain the FSH record, but also terrified of letting anyone touch the car other than me, and this includes of course the agents, so would try and DIY as much as possible...