Terry Harper wrote:

I'm fairly certain that I used Associated Motorways unaccompanied from
about the age of 14. However, at that time you had to pay full fare
once you were 14, so maybe it is tied to the half-fare age limit?

AFAIAA it's company policy of National Express, but not of anybody
else. I strongly doubt that the X5 would have such a limit, as it's
not really a coach service in the traditional sense, as it doesn't
really have any of the properties of one other than being operated
using vehicles that look more like coaches than buses (though a decker
does show up from time to time).

Megabus[1] seems to state 15+ is allowed, and they don't *have* any
child fares. I actually can't find anything at all on NatEx's website
about it.

[1] Yes, I know the X5 takes some Megabus pax, but it is really just a
Stagecoach United Counties (Bedford) operation.

Neil