We've got them too. Does the stuff you put down for woodlice work on stag beetles? If not, what's the best way to deal with them?
I rescued a stag beetle that had got stuck in a bowl in my garden on Saturday.. Spotted by my little boy. I find people very accommodating to them. And if this thread and the number of spots is anything to go by they are doing well locally.
Stag beetles have a very long larval period (about 4 years) and only a comparatively short period of time (a couple of months) to fly around crashing into things and hoping to find a mate. After they've done the business they die. So it's as important (if not more so) to provide and protect the larval habitats of stag beetles. Rotting wood is ideal, so log piles and beetle hotels are good ways to provide habitat in your garden. We have a number of tree trunk slices dotted around our garden and they all have larvae underneath, which is super fascinating for kids as you can lift them gently and see the larvae, which are as spectacular (if you like things that look completely alien) as the beetles themselves.