Even from the Sth Highlands, though the sky might look impressively dark, it's not as dark as you may think. Actually, even from the darkest areas, the best time to be observing and when it's the darkest is between 10pm and 2am. The reason for this is the Sun is at the opposite end of the planet around this time so you have the whole of the Earth and it's shadow keeping the light away. Earlier and later on, even though it's hard to believe just by looking, the sunlight is actually starting to creep across into the sky and brightening it ever so slowly. Then if you have moonglow as well, zodiacal light (that's light shining off dust in the plane of the earth's orbit), and a faint glow from the cities in the distance...well you don't truly have a dark sky.
You'll know a truly dark sky when you get to see one
It's that dark the sky looks like it's shining and it has a deeeeeep 3D effect to it when you look at it. It's almost like you can see the stars at their distances from Earth. It's a weird feeling, especially if you lay on the ground and just look out into space. You can very quickly become dissociated from where you are and it feels like you're actually floating in space. If you're not ready for it, it can really throw you into a spin. If Venus is up in a sky like that, it can be a bit of a pain as it's too bright. Can actually cast shadows. But you'll never forget a sky like that. It's a real treat to be able to see 11-12 of the Pleiades, M31 looks like a long thin mist, the Magellanic Clouds are awesome to see and if you know where to look and they're up at the time, both Uranus and Neptune are much easier to see....little blue-green dots
I've been to a few places like that....it's a privilege to have been able to see the sky like that. Very few people get to do so.