Thanks guys,
It is indeed a monument to Sir William Wallace, it's pretty much a fixture of the skyline in Stirling. I dont know much about the archetecture but now that its been mentioned, yeh: the top is quite unusual.
Damn, now I see it I wish I had been able to hide that building, there is also a shortening effect as it was taken from the car park of my old work from below looking up the hill. I will be keeping an eye out for that in the future though!