According to Regulation 7(2) of the Money Laundering Regulations 2007, solicitors must apply Customer Due Diligence (CDD) measures at appropriate times and on a risk-sensitive basis for existing clients. The Law Society's Practice Note on AML suggests performing CDD for clients with a gap of three years or more between instructions. As it has been over three years since Emma last acted for Neville's Digital Marketing Company Limited, standard due diligence is required before proceeding with the new transaction and ongoing monitoring should be conducted. 

Key Point: This question assesses the requirement for ongoing customer due diligence for existing clients after significant time gaps, as per the Money Laundering Regulations 2007. Solicitors must stay current with regulatory requirements to ensure compliance.