I'm not in London but there's presumably a decent amount of metal in it and I usually put such things outside with a note on it to please take and a rag and bone man makes it disappear within a day or two. I now have a rag and bone man's mobile number, but haven't had to use it.
I saw a documentary a while back about guys cruising around grabbing any scrap metal they find, the main issue seemed to be they'd be a bit fast and loose with what they considered to be "abandoned".