I came across this issue when I first came to Europe, my new employers wanted me to gain the Multicrew hour requirements for the ATPLH by flying as Co-Pilot in a VFR Bell 412 operation. Of course the B412 POH describes minimum crew as one pilot for both VFR and IFR so I decided to call the CAA in the UK to clarify. They told me that the hours could be accepted towards the multicrew requirement for ATPL if the operation requires two pilots, for example if there is a contractual requirement with the client, EMS for example. That was not the case in this operation so I didn't log the hours and just flew long enough as "helper" until they gave me a P1 job in the 412.
Hope this helps