Towball height

This is not really a Land Rover question, but I thought that someone here would know.
I bought my Discovery 2 to tow a caravan. Caravan is now moved, and I'd like to buy a flat-bed trailer. This was my first time towing a caravan and I have never bought a trailer.
The car's tow bar is not height adjustable, and I was wondering: when I buy a trailer, do I need to ensure that its towing eye is of a height from the ground which is compatible with my tow-bar? I have done a bit of web searching and I have seen that there is a legal range of values, but I am wondering about safety and stresses on both car and trailer if say the tow-bar is too high or too low. How much, if at all, does it matter? And, are most trailer towing eyes set at a general common height, or do they vary greatly?

If you have a Disco 2 then you should be able to either fit a Dixon -Bate or an adjustable plate, if you do not want the degree of flexibility that a Dixon-Bate gives you, and they are cheaper.
see here for both
https://www.google.com/search?q=tra...22i29i30l6.7089j0j15&sourceid=chrome&ie=UTF-8
If your trailer is twin axle it makes a lot of sense to get the height suited to the trailer tow ball, both loaded and unloaded, which is why I need a Dixon-Bate. Not quite so important with a single axle. But the last thing you want is for the tow ball to be too high as it shifts the centre of gravity in the trailer to completely the wrong place.
This tells you about tow ball height,
https://caravanchronicles.com/guides/understanding-all-about-tow-ball-height/
but for me the most important thing is the weight at the tow hitch, it must be sufficient to stop the trailer fishtailing, and the maximum nose weight is in the manual for the Disco. Can't remember it off hand.