Thanks all
.
The bands are still more common than people realise, they have been around for at least 10 years now and though I hadn't seen one for a long while, I was surprised by how many people on Facebook still catch ringed dogs on a regular basis
. They have also been found as far afield as Anglesey and Mostyn ?.
Personally, I don't think it's being done deliberately, as it's been happening for so long and it would mean that someone has been placing huge numbers of rings on dogs without being found out, so I'm leaning more towards either lost cargo off a ship, or o rings on some other common marine equipment, such as pots.
The rings themselves are made of quite stiff rubber and are rectangular in cross section, but I can't help thinking that if they were off pots then surely someone would have recognised them by now
.