Cheapest I've seen thus far is £170 + £2 P&P each; £344 for both of us, from Cabair, for half an hour, I'm hoping to find much cheaper.
Daft thing is, this is me trying to plan a fantastic date for tomorrow, so very very late notice! but the upside of that is maybe I could give them a call early tomorrow and haggle them down. Don't want to leave it to chance though (I've got other plans if this isn't viable), so I'm going to continue looking myself, and I'm posting here in the hope someone else will know of / have seen / find something :D
P.S: I realize it's going to be pouring with rain, I wonder how this will affect visibility...