I did take some pictures, but even better than my amateur efforts there is a good video from Lelit on removing the brew boiler, I followed the steps here:
It was extremely helpful to mark the connections to the boiler to make reassembly easy - that was the best tip from that video. e.g.
I also put a sticker over the power switch, marked “RESET” to make sure I remembered to reset after the procedure (don’t burn out the heating element).
