BPRA and CGT

A quick question that I can't find an answer to....

If a claim to Business Premises Renovation Allowance has been made and the property is sold within 7 years, a balancing charge is made but if sold after 7 years there is no BC.

So if the property is sold more than 7 years after BPRA is claimed, is any Capital Gain calculated on (i) the excess of proceeds over the original capital cost of the property only or (ii) the excess of proceeds over the original cost of the property PLUS the renovation costs?

The former seems illogical to the idea that BPRA is an inducement to incur expenditure as it represents a claw-back of the allowance, the latter seems generous.

If the latter, can you point me to the legislation that confirms this?

Thanks

AndyC