I'm trying to replace my halogen downlighter in my bathroom. It was installed around 2009 and I'm in the UK. The downlighter is in a waterproof cover because it is directly above the shower. I can't work out how to access the bulb. I can pull the unit down from the ceiling about an inch, and I can twist the bottom of the unit about 1/8 turn, but nothing seems to come apart, and there are no visible screws. I've attached a photo. Can anyone advise on how to proceed? Thank you.
It looks like Aurora series downlights:
for example, here is some catalog.
Judging from photos, their springs are above than that riveted steel, which is BTW might be another spring holding bottom cover (on the catalog many models with same or similar body but with different cover).