How does Freetrade make money?

Well I saw little on how Freetrade is becoming profitable.
In their deck (on Crwodcube), they expect 263k clients by the end of this year and revenues of £5.2M. They also expect 25k clients as “alpha” customers so £3Mk (assuming it’s £10/month).
That is only like 57% of their revenues so I am genuinely wondering what are the biggest drivers of revenues! Can it only be the 0.45% fee for FX for the remaining?!

Edit: my my maths was wrong indeed as I initially forgot to multiply the monthly fee by 12! Still is accounts for “only” 57% of their revenues