Thats interesting Stuart. I am using the Fulling Mill "Czech Nymph" or the Tiemco "Jig hooks" for my heavy flies these days.
Both hooks, especially if weighted heavliy, fish hook point up the way. I fished them a lot on the Don this year without losing any on the bottom. You may find some in the odd tree though
What I would say though is that due to the shape of the hook, if the line above the fly hits something, then the fly will flip over and the hook will stick. So, if there are branches in the pool you are fishing, then you will lose hooks.
This is the principle that Carp anglers try to achieve with curved hooks. Try it on the palm of your hand, its amazing how the hook kicks round.