I would leave it personally as you are likely to cause peripheral damage. The complete lumbar component alone costs £1,049, if it is the motor, plus any replacement trim that gets broken trying to remove it.
Either that or try and find a complete identical replacement seat that works. Be wary of seat airbags and wiring, so disconnecting the battery following the
BSI Reset / Battery Disconnect / Reconnect Procedure before any attempt is essential and leaving the vehicle for 10 minutes after disconnection.