Prince Harry has been urged to “go and visit” his sister-in-law Princess Kate whilst he is in the UK. Former editor of The Sun Kelvin MacKenzie has waded in on the “pathetic warfare” between the duke and the rest of the Royal Family. Speaking to GB News, MacKenzie said: “This is a long, drawn out kind of war. All families have these issues. “The thing I would most like to see is actually Harry, to go and see Kate. It would be good to see whether something could be done there. “It’s unlikely to be done with the brother. I mean, the father’s got cancer. The sister-in-law has got cancer. “It is i…