I still remember receiving a tax refund for my holiday work in first year of uni, the tax code had been wrong. It arrived some 4 years later when I was in full

I still remember receiving a tax refund for my holiday work in first year of uni, the tax code had been wrong. It arrived some 4 years later when I was in full time employment. I mean, it was a cheer-bringing cheque - but at the same time I found the timing somewhat sub-optimal...