thankyou dizzybint... another charming name IMHO.
i'd probably ask some bfing mums first of all about how long it takes for them to transfer over to formula, or whether it might even be possible to continue bfing in the mornings and evenings and feed them water and BLW food during the day (i know a couple of friends of mine did that with their kids, although it was with purees in them thair days. HVs said their milk would go but it never did).
my experience with formula was that i never made enough milk, so DD had always had formula so there was no transfer period. does dd1 take ebm in a bottle already? yep, the more i think about it the more i realise i'm not terribly qualified to answer your question.
if i was you i'd keep bfing for as long as possible, as you will not BELIEVE the faff involved with bottles and it's a lot to land on yourself at the same time as the BLW. and a lot to add to the baby, too.
but circumstances might change and you might wish to change to FF (and lord knows i'm not going to judge you for it )and it's not too difficult. there is NO information to be found about it but my experience leads me to think that it's much the same as bfing, so long as you are ffing on demand. the one upside, i suppose, it that you can tell the amount they are drinking.
but i think you really want to keep bfing is you can, which is great for both of you. if not, come back to me but in the meantime i'd ask some bfers about how to manage when your dd is at nursery.
i really hope you don't think i'm giving you the brush-off dizzybint, i'm aware that i'm rambling on but i don't think i've helped...
give me a shout if you need anything, and congratulations on your new baby.