I noticed that your poles are quite different to ours...not surprising SM007 cf SM437
Ours, as probably SM422 are quite a lot bigger in diamtre and the end fittings are quite different.
We had also this probleme with corrosion of the Al caste end. We managed to get it out and grind it down to fit the tube, cleaned out the tube end, coated it with lanocote before reassembling, and it has been fine ever since.
Cheers from Gulf Harbour...antifoul done today, propspeed tomorrow, relaunch Thursday