Thanks for everyones responses, sorry not to have posted earlier.
Firstly, I do understand that I am getting a great deal with the
free dining and I am not knocking that, it just seems unfair that even though I have already paid $1600 for tickets (for my family of 5) that covers every day of my entire onsite stay at Disney (14 days) I have to still buy extra tickets to use at the beginning of the stay, because I can't get my package tickets 3 days earlier. When free dining was offered to US residents you only had to buy 1 days tickets for the package, in the UK we have to buy a 5 day ticket which is only $18 cheaper than the 14 day ticket.
Yes, it is good advice to do other things the first few days and not visit the parks, the reason I wanted to visit the parks is that when coming from the UK we are 5 hours ahead of the time in Florida which means on the first few days we tend to wake up at about 4 or 5am (9-10am UK time) and last year we found it really useful as we could easily get to the parks for opening and then leave at lunchtime. I particularly wanted to do this as I know it will be sweltering in August so prefer to visit the parks early before it gets too hot, also part of the reason for the Poly stay was the monorail access to the parks for those first few days. We find that once our bodies adjust to the time difference after the first few days we find it harder to get the whole family up and out at at the parks for opening time!
I think I have basically got the choice now of not visiting the parks the first couple of day or spending the extra $300-$600 for 1 or 2 day base tickets.
I did consider getting a second set of 14 day tickets to use from the beginning of the holiday and then saving the 14 day tickets associated with the package for another trip, but that means I have to find another $1500 before the holiday (even though it will save me buying tickets on the next trip).
Thanks again for all the advice, it is good to know I can get my package tickets at the Poly from the 12th rather than having to go to POR early in the day. At the end of the day I am still happy to be going.
Nicola