Having the wife interested will be a big help Rob.
Having success at school is great. You should get permission about 50% of the time at least. Something that may be helpful in gaining access, would be to offer to look for needles in the bark chipped areas if your detector will pick them up (check to see if it can first). When I was hunting at one school, I was approached by a security guard (who turned out to be the school handyman during the week) and after a conversation, he revealed to me, that the school staff are quite worried about loose drug paraphernalia like needles hidden in the chips.
It's good to hear about Les, although I hadn't met him, I seemed to learn a bit about him through the lady I met. Sounds like he upstaged you.
In the 2 weeks that I was there back in the first half of October, I only pulled out $48 from the beach over 8 hunts,some of those hunts were around 5 hours. Most of that, was on the first 2 nights. I hunted from the water line, back, even near the footpath. I know you aren't keen on grass hunting, but I seemed to do just as well on the cycleway/park just to the north of the beach, where a market site exists. It ends just a few metres north of the rowing equipment that is located next to the cycleway. The store holders set up in 2 and at spots, 3 rows along side the pathway. the ground seems pretty nasty though, with black soil and quartz present in the ground. I pulled out as much coinage there as I did on the beach in the first couple of nights. You might want to use a machine with visual discrimination there, as the is a fair amount of trash in the ground too. Don't waste time on the park behind the beach though, as I got skunked there.
Good luck.
Mick Evans.