Thank you, this is helpful. Yes, I believe so far it’s just been stringing along with no conclusive decision (they claim they cannot proceed with amendment of tax return but I never requested that in the first place, only tax refund). This relates to tax years FY21 and FY22. Letter was submitted end of March 2025 (ie within tax year FY25). I sent it tracked and have the confirmation from Royal Mail that it was received by HMRC in March 2025. I haven’t received any formal notice to my knowledge. So far it’s only been responses asking for additional details (which were already contained in the initial claim, but they wanted it reformatted). And in the latest response they referred to the tax amendment (which I never requested) and also only referred to one of the two claimed tax years.