...to worry that my parcel from Next will be too big to fit on a tortoises back?

[Justmuddlingalong]

I usually click and collect from Next, but I've made the mistake of having this order delivered. Placed the order on 24th of this month, just checked the confirmation email and it will be delivered by the 11th of December. The swines have already taken the money from my bank account, but the order hasn't even been dispatched yet. Is this normal, for not using next day delivery with them?

Only if the product isn't in stock or they carry low stock. It always tells you before you click how long delivery would be. Click and collect wild probably also be 2 weeks on this occasion

Next are pretty good at getting stuff to you earlier than expected. I've never had to wait for anything as long as was initially stated.

They won't have taken any money from you until it's dispatched if it's a directory order, it'll just be pending on your account as a future charge

The money came out on the 27th.