There is no mandatory content for the 'dual training flight'. So yes, a 1 hr IMC training session will suffice - just get the FI to sign it for you.
There is so much nonsense spouted about whether the FI should sign your logbook if he/she isn't happy with your performance. If that was the case, don't be surprised if the FI refuses to sign. Attempt to lean on the FI and you may find that the FI will notify the CAA and suggest that your licence is suspended until you've proved your competence to an Examiner with a LPC.