Seems to be very highly rated by some

But how do you join LR assist....is it just the AA in disguise?

I think you only get it with a warranty.

I've only had it when I've bought a car from a main dealer and it's run for the same duration as the warranty.

It comes with the LR warranty, you don't however have to buy a car to get it. You can buy the warranty separately, which afaik includes LR assist. Not a cheap option though.

And the car may require an inspection. You may only get the B warranty though if you have a car over 6 years old.

However depending on the dealer you are near there are "dealer group" warranties available. I have an inchcape one on my disco which is coming for renewal. Is basically the LR warranty and is provided by CCP which provides the LR approved used warranty. There is nothing that can't be fixed with a hammer😜😜
FFRR 4.4 SDV8 Autobiography Santorini Black.
Fiat 500x 1.4 multiair Lounge 2015
2010 LR D4 Commercial 2.7 TDV6