Yes, as part of a work activity, you can fill UN Approved containers for petrol which have a larger capacity than PCR 2014 gives for a suitable portable petrol container. This is provided all the following requirements are met.
As part of their risk assessment, the petrol filling station may want to agree specific arrangements with you regarding the filling of your containers eg specify which pump they want you to use, time of day when you can fill your containers etc. They may also want to put this agreement in writing.
This relates only to the filling of UN Approved containers for petrol at retail petrol filling stations as part of a work activity.
This does not apply to the filling of containers which do not comply with the requirements in the regulations relating to a suitable portable petrol container, when the containers are filled as a non-work activity.
The petrol filling station, your workplace, and work activities involving the filling, storage and use of the UN Approved containers for petrol, continue to be covered by the Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR), with the requirement to assess the risk from dangerous substances and minimise the risk.
No, the regulations do not apply to a workplace vehicle engine test bed so you do not need a petroleum storage certificate. However, your workplace and your activities involving the filling and use of petrol to run the engines on the test beds continues to be covered by The Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR, with the requirement to assess the risk from dangerous substances and minimise the risk.