@Johnnydxxx actually VLOS is not just being able to make out your drone as a spot of light in the sky ,but being able to ascertain its orientation as it flies, and its relationship to other things around it, actual VLOS distance will vary greatly from person to person ,for me with my MPP which has strobes on each front arm and a single one at the rear of the drone in overcast conditions i can see the drone at around 1200 ft
and know its direction depending on whether i see two strobes flashing or just the one
with my MM and similar sized zino half that distance is probably the limit
in the drone code the CAA have a 500 m max distance from the home point recommendation for drones ,or 1.645 ft and to be quite honest with you at that distance it only the strobes that i can see on my MPP ,and only then on a very overcast dull cloudy day
in bright sunlight thats a whole different story ,the strobes are of much less use ,the main advantage for me of the strobes flying in Wales in the extensive mountain's such as the beacons
is that when i am below the skyline flying in a valley then they really make a difference in knowing the drones orientation ,i would think that this would be the same for you with similar terrain in Scotland