You could also take a top down approach. The CAA Airline Profit & Loss Statistics give totals for handling charges & parking fees (24) & station costs (25).
UK Airline Financial Tables: 2012 2013 | Aviation Intelligence | About the CAA
Download Table 6 in either csv or pdf format.
You can get the number of passengers from:
http://www.caa.co.uk/docs/80/airline...vices_2013.pdf
You will see that, for example, easyJet carried about 51m passengers in 2013 and paid £302m in handling 2012. (Sorry I could probably find consistent years if I had enough time.) Therefore the cost per ticket (departing & arriving airports) is about £6. You can do the same calculation for other airlines. Costs will certainly be higher for legacy carriers.
However there are many ways of allocating costs. If you asked a dozen accountants for an answer you would get at least thirteen replies. What constitutes ground handling and station costs? You could do a long dissertation on it.