I spent HOURS googling for how to disassemble these lamp holders, and even longer sitting trying to get the darned things apart by hand. In the end, as is so often the way, my dad came to stay and he worked it out (although in my defence it did take him hours too).
These lampholders came as part of a pendant which we’re hanging in our hall and landing. We wanted to extend the flex so that one could hang through from the landing ceiling right down to light the hall; so we needed to be able to rewire the lampholder.
The two main parts of the lampholder screw together on a ceramic thread (unscrewing ceramic threads has the bonus of feeling like everything is grinding to dust and breaking in your hands). To up the difficulty a bit, there’s also a little metal catch inside, a ratchet effectively, which keeps the assembly screwed tight and prevents unscrewing once it’s screwed past a certain point.
It’s incredibly hard to see when the lampholder is assembled, but there’s a metal ratchet grip which is sprung up and keeps a ceramic thread. You can see this sharp little metal sprung tooth to the top right of the image below, by the “4A”.
That sprung metal tooth engages with the ceramic metal serations in the lower part of the lampholder.
You can see the whole assembly in place, with the tooth engaged with the ceramic serration below.
So. The next time you need to rewire a 23003.31 model ceramic (or porcelain) lamp holder for an E27 Edison screw lamp, as used in the Mega Bulb by Sofie Refer, I hope you’ll find this small treatise helpful.