I was an apprentice CA, failed my finals(when I look back and in view of current ideals, it was totally due to discrimination - no working experience allowed to me on the subjects required - I was used as a checker effectively)
That said, I took an HNC in accounts after I had my kids, and reached A passes in all subjects, then worked ina number of NHS, commercial, and oil company posts as Company accountant, lead accountant, etc, and now accountant for two charities - 3rd Sector - - so I am what most people call QBE.
I know there's not a great sum involved, but I feel there's a principle involved here. I still think you should ask HMRC, explaining exactly what you did.