Thank you for your question
My name is Clare
I shall do my best to help you but I need some further information first.
How old are the chidlren and do you wish to have extra time with them - if so what pattern would suit you best?
Do you have extra time with them in the school holidays?
You both have Parental responsibility for the children which means that how their time is shared between you is something that must be negotiated - neither parent has more power than the other and if no agreement can be reached then the Court will have to decide the matter
You cannot be force to have the hcildren when you are not able to do so - nor is it reasonable of her to take away time that you have with them unless there is good reason to do so
You should discuss matters with her using Family mediation
There is no reason why you should not have the children Sunday night on "your" weekend - and you are being reasonable in pointing out that your work commitments have to be respected.
You may find this website useful
I hope that this is of assistance - please ask if you need further details