They sell one as a complete unit.
It's a hatch type of installation ....with coax, 12v, TV bracket all enclosed and lockable. Tv just clips on bracket. They won't fit it on all models as it depends on space available.
The alternative is much simpler and cheaper. Just add a 12v socket to external wall with an extra coax point. You can also put a bracket there for the tv to slide into but that's just another possibility.
We got the above and it's simple and easy to use.
Best spot for that is under a fold down table so you can sit tv on that and easily hook up to 12 or 240 ...and use the booster that is fitted inside.