Mark is correct in that they get both as the specific incomes attract the specific disregards.
The £20.00 overall disregard would apply for example if they were also IRO of a chartiable or voluntary payment* which has a £20.00 disregard in it’s own right but is capped at £10.00 when both that and a student loan is in payment (£10.00 from each).
I also spotted you had posted about this is the Academy thread and someone else has answered the status of the person on Academy, but I thought I would check this as well as you have (what is now clear) a typo in that thread as you mention a £100 disregard which had me scratching my head for a while. 😆
*but that might have changed in April, can’t recall at the moment… 😉