This is a tough one. I Googled and found two another machetes with a close match with your lined horn grip made by a WHJ. Co. I couldn't find that firm's origin, but since horn grips are rate and like yours even rarer was sourced from the same supply chain as WHJ.
https://www.warrelics.eu/forum/edged...imited-821453/
https://sallyantiques.co.uk/product/...ed-whj-co-ltd/
A EAA forum post shows British machetes with numbers 22, 24 & 25 stamped on the blade. This may also be a clue. These are vintage items and their grip profiles are close to yours. See posts 2, 9 &10.
http://www.vikingsword.com/vb/showthread.php?t=17853
You might try to enhance the maker's mark. See attached. They use Fry's etchant available on-line.
https://rke.abertay.ac.uk/en/publica...eel-components
Nothing definitive, only clues, but I'd go 19th C. British with a medium confidence rating.
Best,
Ed