I am helping someone with (suprise!suprise!) a tax credit overpayment. The O/P was caused by a DWP error affecting a disability element so it is a bit out of the ordinary. If I do not get any joy I am thinking of taking things to the Adjudicator's Office. The Adjudicator's website states that they can deal with issues about "use of discretion". Has anyone any experience of doing this and are there any tips/pitfalls worth knowing about?

I've not had as much joy with the AO as I have with the Parliamentary Ombudsman. One problem with the AO is that they won't get involved until the TCO hs made a decision so, if there are delays in the decision making, they won't get involved. However, if you do get a refusal decision from the TCO within a reasonable time the AO may well be ok.

Because of this, I have only ever used the Ombudsman so I don't know how 'generous' the AO is.

I have found that the AO seems to do everything they can to avoid taking the case on, so I now dont bother and will only use the Parliamentary Ombudsman

I'm a little surprised at the above comments on the Adjudicator's Office. I agree they won't (can't?) take cases on till TCO have come to a decision. However, I have referred 3 cases to them. The first was after the TCO decision. The AO was then very pro-active in getting a report from TCO (which they had to chase for many times)and dealt immediately, thoroughly and most satisfactorily with the case when they had the report. The other two cases were before the TCO decision. In both cases AO wrote to TCO immediately to try and get them to make a decision. In one of these it resulted in an individual in TCO actually taking ownership of the complaint (why can't all complaints be dealt with that way?) and resolving it satisfactorily. The other case is still ongoing.
I know it takes a long time (but that is due to TCO and not AO) but would have no hesitation in going to AO again if necessary.