Excel 2010 IF nested date formula Help needed please

Excel 2010 complex IF, or another solution ? Thanks for looking. Sample table below.

I need to calculate theoretical number of available working days and hours
during contract period , total which varies according to the start and finish
date, but all within the period 01/01/13 to 31/12/13, less the bank holidays,
total of which does vary whether based London(8) or Scotland (5). Then multiplied by
FTE as some are part time. 8 hr working day.

So far .... but can't cater for 2 sets of banks holidays, or a different start and end to contract within the period.

=IF(D2="","",IF(YEAR(D2)=2013,NETWORKDAYS.INTL(P1,\$Q\$1,1,'Bank
holidays'!\$A\$2:\$A\$9)*M2,NETWORKDAYS.INTL(\$D\$2,\$E\$2,1,'Bank
holidays'!\$A\$2:\$A\$9)*M2)
 A B D E H I J K L M N O P Q name emp id contract start date contract end date contract type contract status employee base gender status FTE theoretical working days theoretical working hours 01/01/2013 31/12/2013 Ellie 00015 01/01/2013 31/12/2013 employee perm London Female man 1.0 Davie 00011 14/05/2013 31/12/2013 employee perm London male sts 0.6 Sally 00008 01/01/2013 31/12/2013 employee perm Aberdeen female sts 1.0 Bill 00020 14/06/2013 05/12/2013 employee perm London male man 0.8 Frank 00014 08/01/2013 31/12/2013 employee perm Aberdeen male man 1.0