I didn't actually say I definitely attributed it to them, I said probably, which, on balance, and with the available evidence, was a fair conclusion.
What else makes me think it was from them?
An obviously hand painted sign, with only a mobile number given, which appears tied to a lamp-post more or less opposite where they broke in to the ground and some way from the equestrian centre, and the equestrian centre has its own notice board for displaying notices to passers by.
What conclusion would you draw? It's just about the evidence and the balance of probablilities, if the evidence had pointed, in my view, to the equestrian centre I would have drawn that conclusion, nothing to do with bigotry.
You're right about it being an unnecessary addition to my OP though, but not for the reason you give.