Does the father have any contact with the children?.
You have 2 options being:
You could apply to the court for a Child Arrangement Order for the children to live with you. You could do so on the basis that there have been difficulties in the past and you would like to take the children away on holiday overseas occasionally and you would anticipate difficulties with getting permission from the father.
The courts will only make an child arrangement order if they feel one is needed. This would be a good reason to justify an order being made.
The benefit of such an order is that you can remove the children from up to a month without fathers permission.
I appreciate that you would like them to go for up to 3 months to technically they would have to return and go back a number of times.
The alternative is to apply to the court for permission to remove the children out of the country on a temporary basis i.e 3 months. If you made such an application what do you think father would say? He could say that he would take care of the children for the 3 months while you learn to drive - is this likely?
If I am honest the court may find the reason a little strange. It maybe better to explain it another way being that it is an opportunity the children to spend quality time with your family and for the children to learn about their cultural background. In short the court will have to balance whether spending 3 months with their extended is in their best
intetests. Due to their ages they will not be missing school so on the
face if it there is no reason why they should go. It would be interesting to see what father says in opposition if at all.
I do hope that this helps.