Mmmmm, thanks for the feedback! I can earn that chap's months money in half a day freelancing! I do get around a week a month sometimes more!
It wasn't so much for the money that I was considering doing some instructing, more that I now have a bit of experience that I thought might be worth passing on. But if there's resentment and grief I may just keep it to myself! (and those willing to pay for it!)