Yes. Remove the ovpn extension and just rename it client.conf
No user name and password as it must me stored in the cr file. The PIA web site states that the files are only valid for a short period if not used.
did you have to enter username/password anywhere? - still don't understand why I don't, no log output either?
how can I be sure the VPN connection is being used anybody please?
Ah. That is the sneaky bit. When you are connected via VPN and you visit PIA site they know it is you [emoji12] So you get logged in automatically. Look at the top of the web page and it shows your IP address and Using PIA (or something like that).