08-09-2021, 09:34 PM
In view of the non-originality of the cap/neck arrangement I would use a Dremel type tool to make a slot down each side of the aluminium extension piece, and split it off with a couple of large screwdrivers, posibly leaving a standard threaded neck. It almost looks to me as though that neck may have been soldered onto the original to extend it. If that is the case, carefully melt or break the solder leaving the original bayonet neck or a neck which could be recovered to that desirable state.