Thank you for your question
My name is Clare
I shall do my best to help you but I need some further details
What is the actual pattern of contact?
How long can then be away if need be?
I was meaning this week - if he refuses to bring them back today will it hurt if they stay there until tuesday?
Ah I see - my apologies.
Who moved away - you or your ex?
How far away does he live?
Fine - so only 20 minutes if you have a car - which you do not?
Can I just check - is there actually a bus they could get to him on?
There is no set rule.
In general terms where appropriate it is expected that parents will indeed share the travel between them - unless one parent has moved far away in which case that parent might be expected to bear the larger burden of travel.
In this case a 20 minute journey would not be seen as unreasonable for you to undertake - if he was paying the CMS assessment.
Since he is not I suggest that you tell him that you will deal with the collection as and when he deals with the maintenance
Please ask if you need further details