The major holding threshold, as you say is 5% or 18.53M shares. There have been some big off market trades but I do not think the total is as high as 18.5M yet.
If it is a new player then they might not have to declare their hand yet.
And while SPL has access to the register, it is almost certainly held by nominees who are not obliged (and sometimes not even able) to disclose the beneficial owner.
SPL Price at posting:
$1.26 Sentiment: Buy Disclosure: Held
