The correct answer is: £18,000.
Luigi started trading on 1 October 2012.
In the first year of trade we tax profits on an actual basis (ie those profits accruing in the actual tax year between the date of commencement and the following 5 April.)
This is period 1.10.12 to 5.4.13, ie 6 months.
The first tax year of trading is 2012/13 and we take 6 months of the profit from the 15 m/e 31 December 2013.