The Department for Transport has formally issued a 6 month grace period, meaning that a driver with a CPC card expiring in the period from 1 March 2020 to 30 September 2020 can continue driving. This appears to just apply to driving in Great Britain and not international journeys.
Please note: Road transport operators will need to check insurance validity where this grace period is used.
See full details on the following link.
https://www.gov.uk/guidance/coronavirus-covid-19-temporary-changes-to-driver-cpc-requirements