Looks to me like a screw is missing. On mine the plug is at the bottom and two self- tappers hold the voltage regulator on, not one and a spare Westfalia hole. ( cost extra as an original German fixing hole ) How did that smiley get in there? Appropriate.
Thanks dubs and Yep mikedjames mine was fixed the same , removed 1st screw but can’t access the 2nd cos the plugs in the way and a biatch to pull off wondered if there was a secret to removing it.
Just spade connectors might be a bit corroded. Give it a waddle as you pull it as the actress said to the bishop
Use the Force .. Carefully levering with a flat blade screwdriver against the case may be needed. Its three spade connectors held together in that plug. Or animal method is to find a tiny pair of mole grips and wind the screw out with that...