Thanks for the feedback folks! Mid 90s ties in to the info provided by the seller.
Day off today so decided to take a long hard look at the bike and think about stripping it back to basics. Crap weather + wife at work + kids at school meant that the kitchen became a temp workshop for the morning!
It's only when you begin to take bits off do you realise the pros and cons of a potential project. Nearly everything was pretty cruddy but all came away fairly easily. Headset practically fell apart when removed and I assume had never been properly serviced. Stem is in good nick as are the bars.
All cables are a bit ropey and one is cut completely through the outer casing so all have been binned. On closer inspection a number of the spokes on the drive side of the rear wheel have been caught by the chain in the past and are slightly out of shape. Rear tyre knackered so chucked also.
Hope bb is stuck fast. Tried to loosen it with a Park pin spanner but it's solid! However, it feels smooth and tight so not too worried. It can stay put.
Frame looks good so washed it and gave it a cursory polish. Much of the surface marks polished out, although there are some paint chips to sort. Thanks hamster for your paint recommendations.
So what next? I've yet to decide on how to proceed with this. I may start sourcing a new groupset (any recommendations?) and sell off the current bits to partly finance that. Don't really like the black stem/bars so they may go also. Shiny bits me thinks will suit the red frame. If I start a full build then i'll start a separate thread elsewhere on the forums.