I thought I out to start a separate thread for this, rather than continuing the thread I started in chat to try to identify it. It has obviously been converted to single speed dropouts and I assume it originally had a canti bridge and more cable guides that were removed at the same time.
It has two frame numbers on the bottom bracket shell:
which suggest it may be a '93 frame, though that could be completely wrong.
The bottom bracket shell is 68mm and the seat post is 30.0mm.
I finally finished off stripping it down tonight and with the seat bolt and 4 bottle cage bolts in it weighs pretty much dead on 2kg.
I need to have a look at the Hope headset, as it wasn't very smooth and then reassemble it to take it for a spin to check whether it's big enough for me before I make any more plans for it.
I've managed to get a crankset that will be perfect for it - pictures to follow - that I couldn't resist and is very similar to the one I decided on for my Karakoram Elite