Hello Nobby,
Your correspondence with us so far seems to have spread confusion, and it stems from the very limited detail of your descriptions. This suggest you are not very familiar with electrical systems, and that has to be a concern. Even though 12V dc power systems aren't likely to give you an electric shock, incorrect wiring can still pose a problem with short circuits and poor connections melting insulation and starting fires.
I strongly urge you to find someone who is competent to come to your caravan and help you sort it out. and to ensure you are using it correctly. A mistake at best might ruin the television and at worst cause a fire.