Copied from Public Guardianship Office site...
Concerns about the improper use of an EPA
If anyone has concerns that an attorney may not be acting in the donor's best interests under an EPA, this should be brought to the attention of the Court of Protection. This can be done by writing to the PGO with all available information concerning the situation. The Court of Protection will consider the expressed concerns and if it shares these, will direct that enquiries be made.
http://www.guardianship.gov.uk/theservice/maki ngan.htm
It also gives the relevant form where you can check if the PoA is registered.
However, the Court and the PGO only have powers to look into the possible misuse of an EPA once it is registered, or where it is clear that the EPA needs to be registered and contact details.