its amazing how few people actually read what the Q is.
first, 150 quid is ample.
in your case, old and reliable is better than new and fancy.
look towards the Olympus Om range. the OM1n is fully manual, the Om2n or Om2sp have the auto option, and their metering system is without doubt, far better than anything nikon ever did. and if youre feeling flush, go buy a Om4ti...
i have had one for over 30 years, and like all my other Olympus cameras, it still works like it did the day it came out the box.
prices vary, an Om2n /sp is about 50 quid, an Om1n, 35 quid ish... and epect to poay upto, 150 quid for a Om4ti, but you ought to get a couple of lenses thrown in.
as ever look on ebay, or if your serious, im in coventry... i dont use my 35mm kit anymore, as i now have all Olympus digital kit.