I’d say thats a late(ish) 1950’s machine. Still has the full circle hand wheels and long gear change lever on the feed selection box used on the older machines. Looks like a non-safety type clutch lever too. Later style bed foot at the headstock end too. Late 1940’s-early 1950’s versions had a sub sided foot, often with Harrison cast in. If the lack of plastic ball handles on the levers is factory rather than shop made replacements for broken balls it would narrow things down even further as this appears to have only been done for a short period. Harrison liked their screw on plastic balls.
Generally a nice solid machine. Simple feed box rather than screw cutting box id spit of s pain for general work as it’s hard to get appropriate feeds for a range of jobs without changing drop gears. Ideal candidate for a (hefty) Electronic Leadscrew System.
I never really got to grips with the snakes’n ladders speed selection diagram on the infrequent times I drove one.
Clive