I've sinced renamed both SSIDs which is not obvious since there are no instructions to do with and no option that explicitly says "Rename". I selected Wireless under networks then simply typed in...

i also tried connecting the ps4 with a cat6 LAN cable which the manual says is straightforward but the connection also intermittently drops

my ps4 can't see the 5g network and there's no way to make it look for any specific frequency

@am304 I've just bought a REC450 too. To start with my PC would connect to the extender using the 5G option!! My PS4 can't even see the extender unless I reboot my PC and now that my PC is connected...