Hi snapper. Hope it turns out OK. Have a good look at the light seal foam and the mirror cushions. If they are even slightly sticky it needs a CLA and the foams changing. I am sure you know about the prism foam - under the top cover the OM 1s and 2s had foam on top of the prism that degrades and eats away the mirroring - shows up as "stains" along bottom of viewfinder.Finally, success! Om-2n body, £40, looks in a decent condition
I would recommend getting in touch with Mike Spencer at http://www.camerarepairs-r-us.co.uk/ and think about a service - he only charges around £45 including foam replacement, and if you are intending keeping it for a good while, it would be a good investment.