They certainly couldn't tape it, but I'm sure some sort of compromise could be reached for it to work. Firstly, bear in mind that the capacity of Wembley for a wrestling event would be in excess of 100,000, which in itself would probably generate the equivalent of about 50,000 buys to the kitty. Then if you consider that the event occurs during the British school holidays, and you could start it at 10PM local time, and it would air at 5pm EST, which isn't really that much of a compromise on a Sunday afternoon. It would rape the infrastructure a little to have it finish at 2 in the morning though.
It's funny that GuyCompton said about Bragging Rights, because that would actually be the perfect PPV to have in Europe. A quirk in the differences between American DST and the British one is that the time difference is reduced to 4 hours in the last week in October. That means that a local start of 9.30pm would be an EST start of 5.30pm, which is later than the current West Coast start time. It also means the event would finish before the tubes finished and everyone could go home happy. It could work, but they'll probably never risk it.