So I was a little concerned to see that my £620 spend with Amex travel had posted to my account with two £310 transactions... but reading here I should be OK because the cumulative spend is high enough?
I got the email saying that "You just used your American Express Travel offer" so I know it tracked at least.
I have another of these on a different card, but I think I'm going to wait for the bonus to post before trying to use it (as I can book cheaper elsewhere).