A useful site if you're contemplating this, or if you want to fit different forks for whatever reason, is http://scandalon.com/2009/06/motorcycle-fork-diameter-chart This lists machines based on their fork diameter.
I eventually sourced a set of pattern gaiters intended for a modern Hinckley Triumph Bonneville. These came complete with a set of thin metal clips (the dark coloured ones at the top of the picture), which I thought were a bit flimsy. So I acquired a set of Moto Guzzi wire clips (the ones at the bottom of the picture) which are a lot more substantial.
When fitting them you have to take the forks off to get them over the fork legs, which is a bit of a chore, but as luck would have it, I had to remove the forks anyway to get the headlight brackets onto them (see earlier post), so killing two birds with one stone.