Lee - I was thinking about this some more. Feel free to ignore the following completely, and I hope it doesn't upset you.

You might want to make sure DD1 is as ready to wean as she can be, although you don't intend to do it. By that I mean things like: making sure you have found some sort of other milk that she likes, making sure she has the hang of cups and so on and can give herself a drink when you are busy with bub2, and starting now to get the idea into her head that sometimes she has to wait for a breastfeed, or maybe have something else instead.

If you do have to really wean, and she associates all these changes with the new arrival, that could be more traumatic for everyone.

hugs
Kate