Member Info for SirBeancounter

Good question! Frustratingly I couldn't spot a rationale in the prospectus (what a horrible skim read).

Just an optimistic guess, but IGG holds loads of capital just in case an adverse black swan event resulted in major losses or margin calls (as everyone already knows).
By having this £1bn debt facility, could it enable the company to hold less capital, therefore return more capital to shareholders in future?
Or, could the debt facility just reflect an enlarged client base and enable further expansion - which would also be good news for shareholders.
Obviously I don't know, but the optimist in me hopes they have done it for good reasons.
Anyone else got any ideas?