Job as a courier / messenger?

What if the guy asking has no knowledge of London and is actually a bit scared of traffic and bendy buses and is allergic to rain and can't fix a puncture or read a map?

If he i allergic to rain and scared of traffic he probably wouldn't be asking for advice about becoming a courier would he? If, however, he wants to know about the pay he can expect, and the realities of the job, I think he'd be better off listening to people who know what they're talking about.