Cheers, mate - thanks for the welcome!
I think I have now answered my own questions after wire-brushing some more gunk & rust off the side of my anvil. It is an English ATTWOOD. It has had a hard life.
There are a lot of chisel marks obscuring the letter stamps, but below the brand there appears to be an "S" and maybe a "T" - possibly once spelling Stourbridge.
At the bottom is "WH". After looking at a few online photos of Attwood anvils, it is suggested that this might be the mark (initials) of the man who forged it? I have seen one other WH and also DC. The letter stamps are "sans-serif", which suggests a later production period - early ones (c1840s) appear to have letter stamps with serifs. I am guessing early 20th century? (...or certainly first quarter.) Length is 26 inches.
My anvil also has handling holes and a flat base.
I will continue to clean it up and then make a mount for it. I think I will need to build-up the cutting table, which is fairly well eroded down from years of hard work. I had originally thought the top face was original and pretty good, but after cleaning off some muck, it appears to have already been welded and built up. Must get a ball-bearing! Rings well and light hammers rebound quite nicely!
Cheers to all. I have already learned a great deal from this forum! Thanks.