GLM 5.2, an open weights AI model, was tested on preparing quarterly value-added tax (VAT) returns for a small UK business and achieved near-human accuracy at a significantly lower cost. The model processed 59 transactions in 68 minutes with a high degree of accuracy, although it made some mistakes, including a serious error in handling founding shares. The test results suggest that book-keeping is becoming a solved problem with the help of AI. The company behind the test is working on a solution to make this capability available to UK startups and SMEs.