I've travelled on the Orlando route quite a few times with my kids, the packs can be a bit hit and miss.
From Glasgow they either get handed out onboard, or at the gate during boarding. That's if they're loaded at all as they frequently forget to put them onboard or run out.
At Manchester they typically hand them out around the gate area before boarding .
The packs themselves used to be quite decent but with cutbacks etc not so good these days. They used to include a baseball hat and the bag itself was decent quality, you used to see loads of people walking about Disney World with them so it was a nice bit of advertising. Now all you get is a cheap draw string bag, a colouring in book and some crayons. Nothing worth writing home about.