Thank you for your question
My name is Clare
I shall do my best to help you but I need some further informtaion first
Do you trust her to keep to any agreement she makes regarding contact?
In that case yes a simple letter is all that is required - there is no need to involve the courts.
However it would be sensible to include all that has been agreed in terms of Contact so that there is no doubt about what was discussed.
I hope that this is of assistance - please ask if you need further details