I just checked online again, the ring you tried on, the new version of the onyx clash ring, is actually fairly well priced luckily!
The bracelet version is more of a budgeting piece for me (37,500 British pounds), something that would need to displace a big wish list item to justify.
The other three I listed below are easier to add for fun, similar pricing to other standard items.
Below, I am using the UK website to compare the items, since none are available on the US site (where I am), and I do shop at Selfridges also.
onyx diamond clash ring - new version, vertically layered onyx and spikes
11,800 British pounds
onyx clash ring - old version, inner circle of onyx, no diamonds
5,000 pounds
onyx clash bracelet - old version, inner circle of onyx, no diamonds
19,700 pounds
I wish I could add pictures, but I am on the desktop site and not sure how to add images here.
I am wondering if you (or anyone) has seen or tried on the old versions of the clash bracelet and ring. If so, what did you think? Are they worth considering? Onyx is one of my favorite stones, and I have a few

Cartier pieces with small pieces of onyx, but only in WG.