Greatnan I think that research applied to younger babies, then followed through to toddler- dom. Babies left to cry more clingy later - which is possibly behind this style of child rearing.
I'm sure Jeni that she is not scarred for life by being left to cry for 7m.
Your DD needs to be clear with the childminder what she wants and expects.
However she might find it difficult to find any childminder who is willing to behave exactly like mum - it is a big ask to nurse her off to sleep in arms, or lie down next to her, when there are other children to be looked after. Too big an ask really - not realistic unless there is a 1:1 arrangement.
But jeni my love, this is not something you can sort for them. Your DD has decided, with some determination, to adopt a particular style of childrearing. There will inevitably at some stage be some separation pangs on both sides and they have to get through this. The choices are really:
1. be velcroed until child starts to separate (i have seen this happen with breastfeeding addict at around 3 yrs... oh, I'm not part of mum, I'm a boy!!! I'm going to climb trees!!!!) But 3 year olds too can be horribly clingy - both mine were at that age and cried if i went out of sight.
2. Try to work at gradual separation now, which will almost certainly involve some crying - the child will inevitably try to control mum and get her close again by crying. That is what babies do to try to control their environment.
3. Carry on as normal at home, go off to work, and let childminder find a way that can work for her.