Debtinfo, if James has always paid the same amount to the IPA and that included the tax, and it wasn't reduced after the tax year, then surely the OR will owe the tax back?
i am presuming that because he has paid the same amount all the way through and only one amount was ever mentioned that the tax was never collected at all. This would fit with the culture at the time that the tax amount being so small would not be collected
ie they never used to collect if amount was below £50pm