A Frayed Knot

At a friend's house this morning, he was having a "yard sale", having to move from his lovely home overlooking the sea, and parting with a lot of his collections and possessions, and I spotted this hanging on one of his doors. I didnt want to ask if it was for sale just to avoid him having the opportunity to reply "Afraid not" hehe.
Good luck Pete, one door closes, another opens, get your foot in it as soon as you spot it, opportunity could be on the other side!