Thanks all,
I made contact with Tony over in lathes.co.uk and this was his response:
Yes, you've identified it correctly, it's an American Barnes of the "twin-leadscrew" type. A well-made lathe that used good-quality materials in its construction.
My article about them here: **LINK**
Barnes were once a very popular make of inexpensive lathe and became almost the "backbone machine" of rural American repair shops from the late 1800s to the 1930s. Today many are still in daily use in the USA – and not unknown in the UK to where numbers were exported (less identifying badges) from 1900 to the 1930s. None of these lathes have any technical merit or interesting or unusual design features – and hence sell for only a modest sum.
Barnes were a very conservative company who changed their lathes only very slowly over many years and, although they never published an "Instruction Manual" in the modern sense of the word, their sales literature was very interesting and I have two example below that you will find of interest: