@MouldS is the working X account: 30,704 followers, 4,360 posts, joined 1 December 2008, with a bio that links youtube.com/stevemould, a booking page at stevemould.com and a Patreon, and describes him as "One third of @fotsn".
The similar handle @stevemould is a different person entirely — 10 followers, 18 posts, located in Worthington, Ohio. It is the sort of mix-up that survives into published articles.
We could not read either timeline. X blocks automated access to posts, and the profile lookup we used returns account metadata only. So this is a directory entry rather than a review: we can tell you the account is real, large and long-running, and that his subject matter is science video, but not how often standing waves or Chladni patterns turn up in the feed.