If you put, replacing caravan aerial, into Google you may find what you are looking for. Quite a few results.
------------- XVI yes?
As well is two words!
How does a sage know everything about everything? or does he? or does he just think he does?
Remember, if you buy something you bought it, not brought it.
I replaced our Status 330 with the taller mast model 560 directional aerial. Not a difficult job but maybe not one for the faint-hearted either, especially as you need to accurately drill a 50mm hole straight through the roof.
If you haven't already done so, download the installation sheet from Grade UK using this link, have a read through the blurb then come back with your questions.
Incidentally, despite the higher cost of doing this over using an external aerial, the convenience and speed of set-up is excellent and worth the upgrade in my opinion.