So, they've been back. Apparently there are a few groups roaming the area and only one of these was scared off last week.
We have another hunter guy now who's been sitting on our terrace for the past four hours (8pm-12). He's gone off for a wander around with his shotgun under his arm before he calls it a night. No luck tonight, but he has seen deer and foxes in the garden.
Glad he understood our needs. Boar and only boar!