Licensing differs from state to state, but I know in Qld and WA there are a small number of Centres that are licensed for smaller groups e.g. max 21 chn, that run family grouping scenarios as you've mentioned. Usually you will find they can have a limited number in each age group within that one group i.e. no more than 4 chn under 2yrs, 8 chn aged 2 - 3 yrs etc. I am plucking numbers out of my head mind you as it's been a few years since I've been involved in Licensing - just wanted to give an example! A balanced program/equipment can be provided for the children, provided the staff are the right staff and dedicated to their job - just as in any Centre! You might find the age groups even though sharing the same environment, do quite seperate experiences/ utilise play spaces seperately/ generally the younger ones might eat and sleep seperately....it's all up to each individual centre.

It doesn't sound like the carer explained the programming very well either - ask for much more info! As for 'assessing' each child, all centres do that in the form of observing, planning and evaluating, and this can be done when running a mixed age group. E.g. when the toddlers are sleeping you might find the preschoolers doing threading or beading etc to minimise risks. When it is well planned and implemented, this kind of care can work really well, and be more like a family day care/mixed age grouping setting, but if not managed well it can always turn into a mess. Like any long day care centre!

It might pay to observe for a few days, and if you can, do some of the observing at drop off and pick up times and approach parents of other younger chn in the group and ask how they find it. Check their accreditation status and history also.......or, if it's ringing alarm bells for you and DH maybe just look for a different model of care, as you both have to be completely comfortable with leaving her there.

HTH and good luck with whatever you decide