Oh dear, what have I gotten myself into....buying the SJ4000 has opened up a can of worms, as I can't stop looking and salivating over accessories, there's so many I want!
After hours of playing about, I finally figured out what all the mounts and bits in the box does, and I've finally got the SJ4000 in the waterproof case on a quick release catch on the strap on my rucksack. Success.
Considering one of the mounts is a standard tripod screw one, that opens up a huge world to what extra mounts (tripods, selfie poles) I can get. And after watching a review video on mounts on Youtube, it seems I can use GoPro mounts for the SJ4000 (but not vice versa).
To future-proof it, I'm trying to hunt down a lens cap of some sort. I might have to slap a lens filter kit on just to get a lens cap.