Another thing to consider is that there is some doubling up in the Top 20, meaning that the same shareholder has stock issued in 2 different names, meaning that the Top 20 is tighter than it looks.
Similarly, as
@Lefevre so correctly pointed out, it's the large holders who'll determine what this share price does.
When you consider that if you account for this doubling up in the Top 20, if you're holding 600K shares you'd probably make the list. And believe me when I write that if you have 600K shares, you've been well and truly vetted as being a loyal, LT shareholder.
Consequently, with the buying that I'm sure they have lined up as well as the tightness of the register, SE1 will be a great performer in the ST, MT and LT.