ColoRyan, that Mercian is one special frame. As for the rest of it...personally, I would pull the parts and toss them in your spares bin, and find a suitable set of SR/Suntour parts to go on it if you're on a budget, or Campy NR if you're not, and set it up as a sports tourer, which is what it originally was.

The seatpost looks like an Avocet. Be careful with the Avocet cranks, I broke a number of them back in the day. You're missing a chainring bolt anyway.