When you refer to "get my Olympus 35RD serviced", does this mean you've actually bought it, or are you just thinking ahead?
£100 for an RD sounds like top whack. I saw one in a camera shop not so long ago for £30. If I was paying £100 I'd expect the camera to have been serviced and ready to go. Have you thought about a 35RC instead? They're a lot cheaper and plenty more to choose from with only a relatively small sacrifice in specifications. I have an RC that I just keep loaded with b/w film as a take-everywhere camera and the last roll I developed surprised me with consistently good exposure worthy of a much more complex camera. The lens on the RC is excellent up to 10" x 8" enlargements and probably a lot further, though I've never tried.