Oh dear- wish I had read this just a few weeks earlier as I have purchased a set of 4 off 
for the rebuild - marked Aldan American 10-700 on the springs, from Halls. Halls said this was their recommended premium drop in shock replacement.
Ah well the information on the Gary leak repair method may well come in handy in future Bosswrench - most appreciated !!
I must say they do look like a very good quality product - Beautifully finished, but the road will eventually reveal all!
I will update once I actually have an informed opinion on the performance.
Still slogging away on the back suspension rebuild! All bushes , bearings in but still waiting on some small parts for the lower shaft reassembly. Getting there.