Access into lounge with Plat card but no priority pass

Posted here as this is kind of amex card related.

Partner got plat card late last year but the priority pass didn’t arrive on time before we left the UK hence no info to be able to register the PP account.

Is it possible to access the lounge with just the plat card? Any other ways around this is much appreciated.

Ps. Understood that normally plat card can be used to access the Plaza Prem. Lounge. But how about other lounges that are contracted to Colinson (Priority Pass)?

Many thanks,
Vit