Just got off the phone with CARC and the club.
CARC have said that the process of validating my PPL is not something they would do, only a conversion. Apparently, validation of licenses is only for CPL/ATPL level.
They advised me to speak to the club again. Having done so, they have elaborated that whilst they normally consider me the PIC (handling controls, communication etc), it seems that if anything were to go wrong the safety pilot would be taking over and that the Jordanian certified pilot is the one ultimately responsible for the safety of the flight. Assuming I understood them correctly, this seems somewhat off, and would suggest they haven't appreciated the definition of PIC.
I'm guessing it is also unacceptable under EASA, even if the club and CARC are happy to condone it.
They did guarantee me that the Jordanian certified pilot will not be logging PIC at the same time as me.
I think I will have to look into it further and either get an agreement that I remain PIC in case of an emergency or else pursue getting a Jordanian license if I remain set on some hour building here. By the time I am back in Jordan early next year, I should already have the 100 hours total time required, and possibly a passport sorted.
I've sent off an email to CARC's licensing team asking them to elaborate in any case, could be a while until I hear back from them though. The joys of dealing with Arab bureaucracy...
With regards to the general concept of a safety pilot, I also previously have only heard of them in the context of instrument flight training and supporting pilots with medical limitations in case of incapacitation - situations in which their role is clearly defined. However, in addition to my example, there does seem to be another organisation offering 'safety pilot's for the purpose of hour building in a foreign country - the AGP based one I linked to above. Does anyone have any experience with this sort of thing?