Spur or not is irrelevant. What's it supplying?Is a spur subject to the same limitations?
In this case is it a BS 1363 accessory, or a CU?
If the latter and not the former, please show how the 2.5mm² cable on a 32A breaker complies.
Are you of the belief that 433.1.204 allows anything else?Are you of the belief that BS1363 FCUs are the only additional fusing method allowed on a ring and/or spur?