DART-3 Module Power Station ! 

This is the recommended 15A Plug Single Phase Plug to install inside your premises Power Box, as the main Power feed too the Premises.

Then you only need a 15A Caravan type Power Cord to connect the Mobile Solar Power Station to your premises.

Unless you Hard wiring in Conduit to a separate Weather proof 240V Housing at the Trailer location, and use a shorter 15A Lead to connect to this housing.