My confusion wrt "I naturally assume that any AR written off by a counterparty should be a tax consequential loss, but Advent's 2024 taxes paid reflected a slightly smaller net profit on sales than in 2023, i.e. 900k GBP vs 1.9M GBP."
What I meant wrt Advent is that Advent's AR due from NW had been booked as taxable income, so if Advent had to write that off and take a loss in 2024, the loss of the AR should have made Advent's 2024 tax liability zero, but it wasn't. On the other hand, if NW owed AP to Advent and Advent wrote off the debt, then that should be income to NW. Not taxable because NW is running a loss, but still, it should show up on NW's books. Please correct me if I'm wrong.