Updating Land Registry - have executors bought a property without disclosure

My husbands mother passed away in 2019, his brothers were executors of the estate which included several properties. Two flats we believe were sold undervalue and the land registry records still identify their late mother as owner of the properties despite several years having passed. Is there a legal requirement to update the land registry? The other properties within the estate have been updated but not these two flats.

Hi Sally - If the land or property is registered at HM Land Registry, then there is no time limit on updating the register.  If the land or property is not registered, then the application for first registration must be made within two months of the transaction that induces compulsory first registration. 
Hope this helps. 

Thank you, the property is registered. The identified owner remains incorrect but as you say if there is no time limit to update the register we remain oblivious as to whether the property was bought by a family member.

Sally - anyone who may have purchased the property would have to produce a Transfer or Conveyance that was executed (signed) by the person named as the legal owner in presence of a witness.