To the sides of my climate units I seem to have an unsightly 4mm gap but can’t work out why as everything is tight?

Last the rear seat hinges look like they should have some kind of covers missing - am I over thinking?

Mine's a 2006 Vogue, so there may be differences, but......
The rear seats have covers on them (Blue, to match the interior ) You cannot see the hinges.
The trim at the side of the HVAC panel has a very small gap on mine, the gap is the same left and right, it looks like your side panel is not clipped in correctly. It clips into place at two points at the side of the HVAC panel, with a holding screw down in the foot well. Hope this helps.

The side cheeks on your heater panel just look like they’re not seated properly. 2002 4.6 Vogue SE - Alveston Red with Lightstone Leather
2007 Range Rover Supercharged in Java Black with Ivory Leather
2012 Range Rover 5.0 SC Autobiography in Indus Silver with Jet/Ivory Interior
2012 Range Rover 4.4 TDV8 Autobiography in Baltic Blue with Sand Interior

For the comments above.

Right… took the cheeks of - lined up the plastic pin and plast expanding plug thing on both side and it’s still the same - the gap seems wider at to top… any ideas 😂 Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

Dan, they can be a little trickey to line up & can take a couple of attempts.

You need to line up the front of the trim at the top with the surround & ensure that the trim clip is located correctly ( then locate with a light thump).
No need to worry about the back of the panel, as you have quite a lot of movement & it's only held in by the one torx screw.

Good luck Paul.