Very many thanks to all of you for taking the time and trouble to reply.
There is much encouragement to take from all of your replies and also enough of the ‘downside’ to be able to give my son a clear idea of how much effort is required and the potential rewards on offer.
Genghis – that certainly wasn’t a lecture! Your well-reasoned view actually makes me feel much more comfortable about my son’s future should he decide to follow that route
Very much appreciated everybody.