The legislation doesn't say split for taper and then revisit the percentage for PPR. It says a proportion of the gain is covered by PPR, but then (nonsensically) you have to apportion the non-PPR element again between business and non-business.
What it should say is split the asset into two assets - the personal bit is reduced by PPR then the balance tapered at NBA rates, and the business bit reduced by BATR. But that's not what it says.
I've had a bit more of a search around, and found similar examples:
http://www.accountingweb.co.uk/cgi-bin/ ... =524&f=525 http://www.accountingweb.co.uk/cgi-bin/ ... ?id=163268Both of these agree with the poster's accountant's analysis, and that the situation is bizarre but true.