David are you referrring to lowland deer, highland deer or just deer numbers in Scotland in general?
I think there is an issue where a few individuals hold a lot of ground (some unshot) to the detriment of others and when the others are lucky enough to get their own ground their only option is to shoot whatever deer are on it to balance the cost and regardless of the impact on the numbers. Not a good management plan but it satisfies the recreational stalkers need.
The Highland Estates are generally well managed and have a set cull target where the herd size is maintained. I was stalking in Sutherland last week and the number of deer on the ground was immense, with the stalker advising that the SNH count seemed low at 400 and from the numbers that I saw I would agree.