Capital allowance claim on car

I have a client who set up as self-employed in May 2009, bringing into the business an audi valued at about £10,500 at commencement of trading. She traded this audi in in the August of 2009, buying a mini clubman diesel, which just qualifies for full 100% FYA (109 g/km). The mini cost £15,100 and trade in value for the audi was £8,200.  Both cars are used 90% business/10% personal.

My question is this - does each car have to be pooled separately as they both are private use assets, or can they be pooled together (both using the same % personal use), with the audi treated as a disposal offset against the mini.  My understanding is that they should be pooled separately, but this would seem to give an excessive amount of CAs with the mini attracting 100% FYA and possibly a balancing allowance on the audi as well?

Any advice welcomed.