Hi Pauly,
I'm not in your area, but maybe a few questions and ideas might work for you as well.
In short I think you did approach the pools in the wrong way. Just put yourself in their shoes, and think of the ideal customer to a pool. Think insurance, think reputation, think numbers, think money, think hyper sexualised culture, think normals. Now I think you'll see that any pool would much rather decline a freediver from coming to their pool.
Next time you call a remote(r) pool, don't tell your name, ask for when the quiet hours are, and how many and what types the normally expect. With the pool size in mind you can estimate the space you may have.
Then just show up with your friend, incognito, say hi to the lifeguard, and start with some regular swimming for warm ups. Leave the (big/long) fins at home, only have a triathlon like suit if you need it. You can bring a small neck weight, but it should look very small and invisible. (Wait with all the toys until you know the lifeguard is at ease with your underwater swimming. It's a delicate situation)
The idea is to easy yourself in gradually, earn the staff's trust, make friends with the other swimmers, be seen as a noble, welcome and honoured human being. The Chinese proverb goes: He who treads softly, travels far.
Personally I've made the mistake of chatting up against the lifeguard, telling him how safe and proficient I am, and sharing endeavours that in the layman's ear sound superhuman and extreme. - Avoid triggering their fears.
Instead listen, empathise, and ask for permission when you feel you can stretch the rules another tiny bit.
Make sure your swims look easy and fun, and your goals are just to have fun and learn to swim better, relax better and be more streamlined. All this improves your scuba experience (..), I'm you understand. Don't call it freediving it's just scuba or snorkel practice.
I hope this helps, please report back how your experience was
Love, Courage and water,
Kars