Sniping against my own bid.

Apologies that this will have been answered a hundred times, but I can't find one!

Suppose I really want something and am prepared to pay max £80. However, there is a very, very small chance that AS will be unable to place my snipe. So for safety I put a lower direct bid in at £75. The next highest bidder bids £50. So do I win at £51, or does my snipe win at one step above my direct bid, i.e. at £75? I realise that I pay AS either way if I win, and am cool about that, but at what price do I win?

Thanks in anticipation.

Anderson