Well I knocked the side of it with the hammer, obviously. I was convinced that the outer ring that is recommended to tap was actually part of the base (5-armed structure that holds the bottom of the gas lift) and soldered to the arms - but inspecting it again carefully I relaize that it’s not: the bottom of the gas lift is in fact sticking out through the hole

Image However, after working on that with a hammer as recommended it still won’t budge (I used a piece of wood instead of cloth this time - and it broke multiple times 😂)