Hi OP
It sound slike you're going through a very tough time for which you have my sympathies.
First off, from what I'm reading here there is a big confusion about what shared residency means. Shared residency means that both parents are considered and treated equally. They both have the right to be parents in every sense and are not reliant on the other parent to give them info and able to make decisions without one parent being unilaterally 'in charge' of it all.
Shared parenting is NOT about the dc spending equal time with both parents. In fact you can have a shared parenting arrangement with much less than half the time with one parent although it is more usual to have a fairly equal split, particularluy when you take school hols into account.
Please look here for more info home.clara.net/spig/
Personally I think shared parenting is usually best for parents and dc. Everyone accepts both parents are equal and noone is more of a parent than the other. Dc get to spend good amounts of time with both parents and benefit from feeling they have two equal homes and aren't just visiting their NRP. However I don't think that shared time is necessarily best just because you have shared residency.
Once you've read more on shared parenting, and given the amount of time your ex was seeing the dc during the day etc, I think perhaps you may agree that shared parenting is OK for your situation. What you should probably be appealing against is not shared residency but the time split that the court has ordered to go with it.
So get your case together on that basis and yes definitely get your case together on the basis that the court have made a decision without all the facts and not in the best interests of the dc involved.
Your nanny sounds wonderful. Do you employer her and pay all her wages. or does your ex give you money to pay his half/share of her, or do you both employer her separately? I think you need to agree with her that you're going to let her go and explain it's not about her at all but you need the situation to improve for the dc and that her being there is facilitating the ex in his strict time rules. From what you've said it sounds like she will agree and understand. Let her know you will give her a glowing reference and do what you can to help her find a new placement.
Tell your ex you are letting nanny go, explain that you don't need her any more as you can do all your work while dc are in his care and can continue to do school drop off and pick ups on your contact days so she's no longer needed by you. Say you have given her notice but that he can of course come to an agreement that he continues to employ her himself. Or another nanny of course, but that must be something he arranges, agrees entirely with the nanny and he must be 100% responsible for the employmentm, contract, wages, tax etc in future for whoever he employs.
Also remind him that he will need to sort out what his arrangements will be for the summer holidays and that he has presumably booked some time off work for this.
Tell your nanny that you have no problem with her continuing to work for ex but she must negotiate a contact with him and he will be responsible for all her salary and tax and you will no longer be able to correct his mistakes or be her employer.
Given that he will only pay her for the days he employs her it seems likely she will look for a full time position elsewhere and can use that as an excuse to go. If you can afford to pay her in lieu of notice then really do consider doing that as soon as you can.
Your ex needs to take responsibility fo rparenting his dc. He wanted equal residency, he wanted a substantial amount of time with the, now he has to show he means it and can actually achieve it.
Yes it may be tough for a few weeks, but you need to show your ex that a consequence of him wanting to share his children and have so much time is that he has to take responsibility for caring for them, or arranging care, in his time. Don't step in and help him out, tell him clearly he has to accept the responsibilty and get home from work to do school pick ups and drop off etc and arrange work around his childcare (just like you are)
Make sure you are clear with him that you are happy to negotiate on the hours/days you have dc if he is unable to do school pick ups. But be clear that this should be a permanent arrangement not an adhoc situation and you expect him to make the necessary arrangements to parent his children in teh time he has said he will take care of them.
If he struggles suggest that maybe it would be better to look at the time split again with you having them more in the afternoons/overnight in term time and him spending a bit longe rwith them in the school holidays maybe.
Remind him that if he is serious about wishing to parent his children equally he will hve to find a work/life balance to allow him to do that and not to simply rely on you to pick it all up because you are now both shared parents and so he needs to be responsible for his share...
Definitely appeal and really push for what you think is best for dc. I think you'll get further appealing the time split, especially as you have already given many reasons above why you feel it is not in the best insterests of your dc. Nanny is allowing court to agree to the time split, but if she goes I think you strength your case considerably that he can not maintain the contact level he is requesting and that a new nanny/childcare isn't in t eh best interests of the dc when they have a parent who is perfectly willing and able and at home ready to care for them.
Good luck.