I booked a flight inclusive holiday with UK Disney so when i ring the UK number i always have to ask to be put through to Openride (the company Disney use)
It was Openride that gave me my 12 digit number. I think others have been put through to guest services and got it from them.
I finally got my 12-digit number from Disney UK, via guest services!

Apparantly they are not supposed to give out this information, but they made an exception.
I also called WDW-DINE to see if they could put my dining on this ressie rather than the incorrect
travel agent one, which they did not understand, so they put me through to the resorts department. This nice CM also didn't quite understand what I wanted to do, however she did find my UK booking (yay!), did some more digging around found out that the bad travel agent booking is now gone (yay!), plus gave me an additional package confirmation number! Yes people, I now have three different formats for the same booking

. Does anyone else have something consisting of three letters and five numbers?
For the dining thing she wanted to put me back through to the UK, but I don't have time for that right now... At least I'm one step further than yesterday!
Btw, who should I call to book the ME: Disney UK or US (cheaper)? I requested it when making the booking, we didn't have flight numbers yet then.
Thanks for your help everyone! It seems that sharing experiences here is the only way to get the booking you want.