daveco: Anyone with any idea/advice on ths one and could it be time barred ? thanks
I believe that they can invoice you up to 6 years after the problem occured, before it becomes statute barred. But as this is government money involves, perhaps the statute of limitations does not apply to them.
My Dad had a problem with tax many years ago and he made a complaint. They agreed to look into the matter again and did another two calculations, with different amounts being provided each time. I don't have much confidence that they know how to calculate amounts accurately or understand how the tax credit system works.
Would suggest that you enter into a complaint with them, which may put matters on hold. This is the complaints leaflet. http://www.hmrc.gov.uk/factsheets/complaints-factsheet.pdf
Huckster