In general, the expectation is that term time contact is suspended during holiday periods and the holiday contact arrangements take precedence. If it's not specified, the court clearly expected the two of you to be sensible and arrange it between yourselves. If you can't do that, then you'll need to apply to the court for a variation.
You could ask for an order in the following terms and state that you think it would be more workable than your current arrangements.
Alternate weekends, Friday after school to Sunday evening (or Monday morning if you prefer - return to school), plus one night a week in the alternate week.
School holidays to be shared 50/50. Or in the specified weeks that each working parent can manage. Term time contact suspended during school holidays in favour of holiday arrangements.
Easter and Christmas to alternate (e.g. you have them Christmas on even years and Easter on odd years and him the opposite).
Mother's Day with Mother.
Father's Day with Father.
Children's birthdays to be shared on an alternate year basis - or for each parent to have some allocated time on the children's birthdays.
Any other contact as agreed between the parties.