I have a lathe of very similar construction, with the main difference being the tailstock. The headstock, bed and carriage are almost identical to yours. Here's the problem, I haven't been able to identify mine either. The only mark on the lathe proper is a small serial number (R114) stamped on the back flatway at the righthand side of the bed under the tailstock.
I have trawled through the site lathes with little success. Mine seems to be a mixture of Grayson, Warwick and Zyto in design.
It may be that we may have to strip the lathes back to bare metal to see if the original manufacturer's name has been chiselled off, as seems to be the most common way of rebranding the english lathes. BTW, mine is also missing a tooth on the bullgear which I'll repair after I have stripped it back and restored it.
Good luck in your quest.