They might fit with some fiddling but the car wasn't designed with that size in mind. What wheels are you using? LR or aftermarket?

To check the ride height setting, measure from the centre of the hub cap to the underside of the wing when car is sat on a level surface at normal height setting. Should be 462mm at the front (from memory) 2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed

I'm currently using 285/35R22's but want to move to the 20" I mentioned and tried. It is a listed size on other websites and seems fairly common in posts from L320 drivers in forums so I expected them to be fine...will see if I can try again without the spacers I guess...

It might be listed on a website somewhere but it isn't a size that LR ever put on the L320. It's a L494 (the second generation RRS) size.

What wheel is that tyre fitted to? A LR wheel or something else? Just wondering about offset. Also, check the static ride height to ensure that someone hasn't previously lowered it slightly. 2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed

Yeah was definitely never put on by LR themselves but I hope it will fit.

Offset is only 45 so I guess the spacer makes that 65 equivalent at the moment, if I am working that out correctly. They are aftermarket wheels:

9X20
5X120
ET45
72.6