Hmmmm, do you think I will get a better response if I send it to them rather than the other, I spoke to their customer relations on the phone (at same address as I have got) and they were absolutely shocking. Really, really unhelpful
Yes you can send recorded delivery to a PO Box. I did last week, and had confirmation today that it had arrived. My employer has lots of PO Box numbers, it's really just to identify which department the mail goes to.