There are a couple of things to be aware of when choosing a TV for a caravan.
For a start where will it be situated and where will you be when watching it? Most of the cheaper small TVs (15" and 19") go very bright if viewed from above the horizontal centre line and very dark - even negative - from below the centre line. Go into Curry's, grab hold of a TV that is on, and lean it over backwards (effectively the same as crouching down in front of it) and see what happens. I got a Sharp L19D1EBK - sadly now obsolete - and it can be laid almost on its back with the picture still plainly visible. Some of the Philips units are the same, but you will find most of the others irrespective of brand are not.
You cannot (usually) fit a wall bracket in a 'van, so make sure that the TV stand has the ability to lean forward if the TV will ever be higher than your viewing point.
In respect of location, does you aerial cable reach? Do you have a Status 315 - if so you will need to replace it or use satellite (which many will tell you is the better option.) It does tend to follow that the cheaper the set the less sensitive the tuner.
Avoid buying own-brand - with a couple of exceptions. The spares - those that are available - are usually extortionately priced. The own brands are:-
Currys Logik, Matsui, Essentials, Digitrex
Comet Ferguson, Kenmark
Argos Bush, Wharfedale
Many of these makes are also sold as Goodmans, Alba, Hinari, etc. and made by about three companies.
The exceptions are M&S and John Lewis who both have good reputations in this field.
Don't get a set with a shiny front screen - to be found on the small own-brand sets in M&S which are otherwise very good. You will have great difficulty seeing the screen, day or night, because of reflections.
Finally, whatever you do make sure you also get a 5-year guarantee. TV's these days are nothing like as reliable as the old CRT's and would normally be expected to last not much more than 5-7 years. Go for somewhere like Sony Centres or John Lewis' where a 5-year guarantee comes built-in, or go to Richer Sounds where you will not only get a good price but the guarantee costs 10% of purchase price, and it is no quibble. You might find some - M&S and Sony at the moment - offering trade-in discounts of £50 if you take any TV of any shape or size, working or not.
Good hunting.