The CAA are perfectly happy for us to practice PFLs below 500' agl so long as we make the effort to stay 500' away from people, vessels, vehicles & structures.
Certainly not disagreeing on that and I know it is widely practised, but is it written down anywhere? The only reason I ask is if I happened to annoy Farmer John sleeping under an apple tree out of sight some sunny afternoon and he clocks my reg I imagine the CAA taking a less friendly approach in court.