“Even if HMRC were subsequently to conclude (at the end of the s9A enquiry) that the loss relief had been wrongly claimed, that conclusion would be relevant only for the purposes of the 2012 return itself; it cannot and could not affect the stand alone claim previously made. For example, as some of the losses were set against 2011/2012 income, that particular set off might be capable of revision by HMRC at the conclusion of the enquiry. However, to the extent that the losses have already been claimed outside the return in relation to income levels in 2010/2011, the only means of challenge would have been an enquiry into the stand alone claim itself. The outcome of any challenge arising from the s9A enquiry into the 2012 return cannot alter the effect of the standalone claim”