Reading this with interest as I've been through this the wrong way and learned all the lessons.
There are 2 key things to get right.
1st is ensuring the floor it's laid on is flat and free of moisture. It needs a spirit level and hygrometer to assess it.
The 2nd thing is having a fitter who knows that, checks it and ensures the floor meets the British Standard that is quoted in the technical specs.
These floors have a very low margin of error for fitting.if there is just a small amount of unevenness in the floor it can throw the edges out and look terrible.
It's easy to get away with ignoring this in a newer build house but harder in an older one.
We had several people come and quote, even from a major carpet retailer that prides itself on doing it right, at least for carpets, that didn't check the evenness of the floor, and only checked the moisture on prompting.
My advice is to watch how the people quoting you assess the floor and you'll know if they know what they are doing.
It can all go wrong from there.
We have a module floor and the product is fine. But the fitting was done badly, with lots of gaps and movement that could have been avoided had it been fitted correctly.
Hope that helps.