(9)For those areas not covered by this Directive, Member States are free to maintain or introduce national law. In particular, Member States may maintain or introduce national provisions in areas such as contract law relating to the validity of credit agreements, property law, land registration, contractual information and, to the extent that they are not regulated in this Directive, post-contractual issues. Member States may provide that the appraiser or appraisal company or notaries may be chosen by mutual agreement of the parties. Given the differences between the processes for the purchase or sale of residential immovable property in the Member States, there is scope for creditors or credit intermediaries to seek to receive payments in advance from consumers on the understanding that such payments could help to secure the conclusion of a credit agreement or the purchase or sale of an immovable property, and for such practices to be misused in particular where consumers are unfamiliar with the requirements and usual practice in that Member State. It is therefore appropriate to allow Member States to impose restrictions on such payments.