I looked into doing this last year, and spoke to a couple of DI'S, one was a friend of a friend so it was impartial/accurate advice.
If its just earnings your looking at then WC is clearly the best bet over a year. Driving lessons vary depending on area but here its about £25 per hour. Sounds good?? Take off the petrol, say £5.00,per lesson, factor in insurance, and wear and tear, and servicing and maintainance costs say £1.50,and your talking £18.50 per hour, before Tax.
As someone said they have to advertise constantly, and offer package deals to attract custom,so competition is clearly fierce. Theres more adds for becoming an instructor on TV than actually offering Driving Lessons, so theres more money in teaching someone to be one, than there is in doing the job.
Incidentally £18.50 per hour for the lessons that actually take place. So you'd have to be fully booked for the year to make it even half appealing, and importantly a large % of 17/18 year old's are apparently very prone to ringing up and cancelling a lesson ,at short notice,cos theyve got a little sniffle / cant be arsed.
Me decided, clearly not worth persuing given cost of training V potential earnings.