Tapster, this is advice that I think might leave you very uncomfortable....sudden cessation even at this stage from 4 feeds to zero is not usually thought to be a good idea.
It is better, and far more physiological, to wind down gradually over a period of weeks.
The other aspect of it - the sudden withdrawal of an important part of your relationship - is also worth thinking about first. To go away - removing you and breastfeeding at the same time - for 12 hours x 2, is not necessary and could leave a one-year-old very upset. She is too young to have language enough to understand, or to 'compromise' with you, as women do with older toddlers.
I don't understand what the allergy consultant's concerns would be. Truly baffled on this one.
Do you really think your dd would somehow take to cows milk in a cup, just because she is not having breastmilk? I doubt it....you might find her nutrition worsens after breastfeeding stops, but presumably your DH and the allergist are ok with that, and assume she will pick up (as she probably will). Either way, where's the rush to do it all, now, at once?
If you feel now is the time to stop (and I am still not sure why - you seem very sad about it ) , then work out a plan to drop one feed a week or so, so in a month or thereabouts she is fully weaned off the breast.
There are, however, sound nutritional and emotional reasons for not doing anything yet!
Hope this helps