Getting the old bearing off was not that easy; Trying to prize it off with a screwdriver each side did not work. The only way I could move it was with a large pair of pliers pulling it in opposite directions until it got to the end of the plastic pin. I was rather reticent to do this but the plastic was fairly supple and bent a bit while doing it. It had seized solid and certainly wasn't worth keeping. Had the worse come to the pin and it had snapped off I could have always made a brass replacement. Luckily it wasn't needed. The new bearing fitted on easily and there was no need to glue it; enough tightness to secure it firmly. Repositioned the supporting pole and came back down. Checked at receiver and it was all working again.
One of the scarier moments was discovering a small number of wasps coming in and out of a small crack in the edge of the roof, right next to the tower I was climbing up to get on the roof. I made a deal with them; don't sting me and I'll let you stay. That seemed to work, and as I moved very slowly past them they ignored me. They are in a concealed roof space and to evict them would mean removing a lot of tiles and felt to get anywhere near them, and besides they'll all die in the Winter and I can seal up the hole with expanding foam for next year.
Mike.