This article and video demonstrate how to use the gas bayonet and the outdoor shower on your Mobilvetta
In your boot or locker, there is an outside shower hose. Ensure your water pump is on inside, located on the control panel.
You will find your gas bayonet on the outside of your motorhome under the flap as per the photo below. When shopping for your BBQ, purchase a non-regulated BBQ as you will be using the regulator and gas from the motorhome. You will need to purchase a hose that connects from the BBQ to the bayonet as per the photo below. Then you turn the grey dial to release gas directly into the BBQ.