Possibly made by Messrs Hunters Ltd. of 16-18 St. Bride Street, London, EC4 and looking rather like the swing-head "Bradley", the Polygon may have been in production circa 1900 to 1930. Thought to have been purchased by a previous owner in 1919, the machine has  unusually pleasing lines with the crank assembly (normally just prosaic lengths of rod or flat bar), elegantly waisted and the operating arm having the maker's name cast in and its outer end formed into a curved hand grip.
With a stroke of 6 inches and a robust 10-inch by 9-inch table (with three T-slots) sufficient capacity was provided to complete most model engineering jobs. The tool slide can be pivoted on the end of the ram - it is held in place by a long through-bolt - and power cross feed provided by a snail cam and ratchet assembly, the amount of indexing being adjustable by varying the position of the pivoting arm carrying the striker pin.
Other Polygon shapers were also offered with one claimed by the makers to be the largest hand-operated machine made in the UK.
If you have a "Polygon" the writer would be interested to hear from you