Hope and MrsFabuloso - thanks for the great ideas.
Hope - I could try no dummy at childcare (especially since she is moving up to the big room next month) and say she doesn't need it because she's in the big girl room?

It's nice to know that other people who also thought it would be a big deal have found it not too bad. I think I'll start mentioning about not needing them as much and mention a 'dummy fairy'. She recently found out about the tooth fairy (from Peppa Pig) and has been asking about that and wanting her to come, so maybe she'd like a visit from the dummy fairy instead?