As case law standas at this very moment in time as Lisa says above the money belongs to you, because the IVA is completed and if you didn't sign anything to say future IVA payments would be sent to creditors.
You could write to them stating that under case law settlement should be sent to you.
Yes it is being appealed but that will be future case low, not present.
so in my opinion it would be in your interests to get this sent to you before the case is heard in court of appeal, because if they find it is due to the IVA then that is new case law from that day forward.
so, if it as me I would write to Barclays quoting the case law in this link and that it has been ruled payment belongs to the debtor (you) and do it sooner rather than later.
googling the case name gives more information too. they may write back saying its being appealed but that's not your issue as it stands law says it's yours !(if you didn't sign anything to say you would pay it over).
http://debtcamel.co.uk/ppi-claims-after-iva/