have had a couple of calls from this number. Given I seldom / if ever answer calls from unrecognised numbers, I wait to see if they leave a message. Which they don't so I think this is either 'cold calling' or a hoax. I'd suggest not answering the call.

Said they were Greenpeace, called my mobile asking for donation. I have never given them my number so do not know if was genuine call. Ended call without discussion, get too many calls of this kind, maybe my number somehow got onto a list of some kind. Will dump this number and get new one.