I was wrong - signing on fees are included in the year that they are paid. Interesting article here from Carlisle United website in three parts that explains it all in detail.
So the remainder of your players make up the total amount of player wages in the calculation you make? Yes, and they are placed under the ‘Contract Players’ section of the SCMP form. As part of the submission you have to include their contract start and end date, salary, signing on fee, forecasted appearance fees, associated bonus payments and any relocation fees they receive. Other player sections to be considered as part of the overall calculation are non-contract players, loan players and players on month-to-month contracts.
Read more at
http://www.carlisleunited.co.uk/news/article/scmpmay2013partthree-804993.aspx#oLI2hkuwCe7ZGUE6.99
I will have a look for the file that I have over the weekend, though