A & C,
You're right...about a year ago a 172 spent a hour circling the new estate I live on in West Berks one Saturday morning.
Curiosity being aroused, I stood on the front path as he circled for a while (at about 800' AGL I would estimate, with what sounded like a fairly low power setting).
About 3 weeks later a man did arrive on the doorstep and sold us the photo for £25. I bought it as it was actually quite good (house smack in the middle) and I am standing on the front path looking up!!
Cheers,
EGTB