december 2010 q3 part a

hello SIR,
following is the note 2 from q3:
2) On 1 October 2012 an office building owned by Problematic Ltd was damaged by a fire. The indexed cost of the
office building on that date was £169,000. The company received insurance proceeds of £36,000 on
10 October 2012, and spent a total of £41,000 during October 2012 on restoring the office building.
Problematic Ltd has made a claim to defer the gain arising from the receipt of the insurance proceeds. The office
building has never been used for business purposes.
i dont understand how is there no disposal on the receipt of insurance proceeds and how the carry forward indexed cost will be calculated?
thanks