Bit more digging reveals that VAT is only on the IP's charges. Advice to the IP's is to keep cases open but it is entirely at the discretion of the IP and they can review on a case by case basis
from
http://www.icaew.com/technical/insolven ... g/iva.ashx
The obligation to make a claim is not automatic or absolute. The
supervisor, in his/her capacity as such, is entitled to exercise his/her
commercial judgement as to whether the steps to be taken are in the
interests of the general body of creditors and, ordinarily, the court will not
interfere with a supervisor’s decision made in the day-to-day administration
of the arrangement unless such decision is fraudulent or in bad faith or one
which no reasonable supervisor in the circumstances would have made.
Such a decision must be made on a case-by-case basis taking into account
the potential benefit for creditors versus the allowable costs involved in
making the claim, both in respect of the potential legal costs of doing so as
well as the time chargeable by the supervisor. In open cases he/she has an
absolute entitlement to charge remuneration in accordance with the terms of
the IVA. Consequently, it is unlikely that a court would regard as perverse a
decision by a supervisor not to seek to reclaim the mistakenly paid VAT if
the costs of doing so, and administering the recovered sum, would exceed
the sum recovered, or result in little benefit to the creditors
Postponing the termination of open cases
Where possible cases which would otherwise be due for closure should be
kept open where a claim has been or is to be made either by exercising the
discretion usually included in a proposal or by seeking a variation. This is
because a supervisor is likely to have more extensive powers in an open
case and could therefore deal with the issue more easily. As this appears
to be a proper exercise of the supervisor’s powers criticism would be
unjustified.
