Try looking at Skytours I think it is. They do guaranteed free child places at some of their properties. With so many of you it will need to be two rooms, so it may be worth looking at an aparthotel that does an all inclusive option.
Also look at easyjet for flights and then medhotels.com. Medhotels have a lot of free child places and is very easy to negotiate to find the number of rooms and the board you want. Obviously you will pay for the childrens' flights. but it may work out cheaper.
Often it is just a case of sitting at the computer and working your way through. Thomson did have free children the other week, but you seemed to have to stay in the eurozone, which isn't an issue if you are AI. Alternatively, set your budget and go into the travel agents with your wish list and see what they come up with. They will give you printed quotes so you can go away, check the reviews and then do an on line price comparison- if you find it cheaper the agent will usually match it.
Good luck!!

Pam

ok pam thanks for the help i'll do that tomorrow and let you no how i've got on.

Michael

Michael, I don't know if it will help, but Balkan Holidays have free kids places in AI properties, some of which have family rooms