Interesting I had not heard that existing ducting could be incompatible with heat pumps. For the wall units, one of mine has a better placement that the other

Interesting I had not heard that existing ducting could be incompatible with heat pumps. For the wall units, one of mine has a better placement that the other so it's not all bad, but the one that is between my living room and dining room is a bit annoying (definitely 1st world problem I know) because my head is really at the right height to get too hot while the rest of my body is still cold. In other words, wall units can still be an option but double beck the placement so that you don't end up constantly crossing the "stream" of hot air.