this is my billhook,
and the top 3 machetes have all been used for this sort of thing. The top one (biggest) is my martindale beast, it's perfect. the martindale golok is terrible, it's more like an axe. and the old manky one is a 9 year old cheapo from ebay and it does a grand job but is just a little short for the big bramble jobs.
I've used full size 'slashers' (big curved heavy blades on long thick sticks) to clear grave yards when I was doing community service and they weren't very good.
Machetes are designed for this sort of thing, which is why they are light weight, sharp and long. perfect for getting the job done without throwing your spine out of place and getting all scratched up. You can get an 18" tramontina latin style machete for £10, I'd say they are a pretty damn good all round machete (I cut modified mine into a sword
) that will do the job better than our heavy traditional British tools.