It's a scam. I've had calls from 'John' and a female, very well spoken, about loft insulation (I'm on a government list apparently which is unlikely because DH insulated the loft), diabetes, tarmac on the drive etc etc. I keep blocking the calls but the scammers use other numbers. It was on You and Yours (R4) some time ago. The calls are from abroad and by-pass ex=directory numbers - I am ex=directory. Thc calls may be AI generated. Today I had another call, well spoken female who said her company was working in my area. She got no further because I blocked her. When DH was alive I took a call about diabetes. If DH had answered he would not have realised it was a scam and would have entered into conversation as he was diabetic so heaven knows what it might have led to.