Effectiveness of DWP campaigns about pensions

Client is a carer approaching pension age. When she checked her NI record she found a substantial gap, and only then discovered (having asked us) that she could be claiming carer’s credit. Normal time limit for a claim is the end of the financial year following the year in respect of which you are claiming, but SoS can extend the time if it is reasonable. DWP say it is not reasonable because information available on gov.uk, and there have been two publicity campaigns since carer’s credit introduced, urging people to check their future pension entitlement. Does anyone know of any evidence or data which shows how effective those or similar publicity campaigns have been in reaching people and getting them to check their future pension?

https://assets.publishing.service.gov.uk/media/5a7ba56440f0b645ba3c5a94/national-insurance-single-tier-note.pdf and https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/184945/ni-credits-changes-consultation-response.pdf.pdf

Paul, I know posted the above on CITA’s facefiendplace. But thought it worth reposting them here in case it sparks off more responses.