Far too much effort for me. ESP when they're so easy to make yourself.
And pretty cheap too. I've spent £15 roughly. If I reasearched the sealant you could cut that right down from the £8 to about 3 by choosing a safe sealant in a diy store. The gun for the sealant was a couple of pounds, and about a giver for a bag of slate.
Out of all that, I have about half a bag of slate left, a third of the sealant, and never have to buy any more sealant guns.
If you take out the gun, I've spent £8.50 on my hardscape which includes 9 caves of varying sizes.
I may make another one as a photo tutorial and to use up the sealant and stuff.