I am full time embloyed and my IVA payments are based on my monthly salary.
I would have an opportunity and time to earn some extra by working as a self-embloyed also. Would I need to pay across all of the extra income (after expenses, taxes etc) or would the 50% rule apply?
Double check with your IP but I would think that you could keep at worst 50%. You are right that you will need to pay expenses and taxes but there also has to be an incentive for you to do the work.