I would highly recommend working with Maternally Yours agency, the staff are very polite, helpful and caring, and always answered any questions or queries you may have.
The staff are very efficient in their work, and take the time to also speak with you on the phone or via a message, they are one of the best maternity agencies to work with.
They are very supportive in terms of finding very good maternity positions both in London as well as abroad. I have worked with Maternally Yours agency for many years and I am very happy with them.