Wow, what a thread [being extremely careful about my grammar and punctuation...]
Just a thought, maybe one of the problems in all this is the idea of just wanting sex?
Also, regardless of the pre/post puberty debate, I'm uncomfortable with a much older person sleeping with a much younger person because it does call into question the extent of 'power' or coercion in place. When the younger person is a child (under 18) and the age gap is large, this is of grave concern as it is hard to be sure the child has the maturity and strength to know whether and how to say no.
Any kind of sex tourism is cheapening the person into a commodity. By the way, legally the position in the UK changed 10 or so years ago so that people who committed sex crimes abroad could be prosecuted following their return to the UK, but it had to be a crime in that country which, as pointed out above, can be very different from UK criminal limits.
I know it's unfashionable, (but I'm a Christian so I'm used to being that!), but maybe sex only for marriage (or permanent relationship if you will) is actually a means of protection from this kind of attitude of consumerism to something deeply personal and intimate.