Hi all - as an update:
I called up Lexus HQ who checked their process - they'd carried out everything according to spec so no faults there.
I've collected our car this morning but noticed 3 things;
1. Car was not washed despite promise that they would (it's their policy to wash all cars that come through the dealership for any works);
2. They ripped a window shade that was placed in the rear passenger window, the other was bent out of shape; and
3. They (for whatever reason) made a right state of the items in the boot and left my windscreen wiper fluid (5L container) open and without trace of the lid?!) - had I driven away without checking, that would've tipped over and created a right mess, not to mention ruin all the other items in the boot and quite dangerously - right above the hybrid battery pack?!
I raised all 3 points with the staff, their response to the above (in order) are;
1. They claim they did wash it - they did not, same bird poop on the roof of the car as when I left it with them and brake dust build up on the rims, same as when I left it with them.
2. They claim they have no reason to remove these - neither do I, they were both fine when I left the car with them and both attached to the windows properly.
3. They again say they have no reason to go into the boot - they claim I must have left it like that when I brought the car to them - there is no way I'd risk damaging the car like this, I also use the boot daily so would've instantly noticed that he lid wasn't on. Furthermore, I have OCD so would've checked the lid is on, tightly, several times before I'd close the boot whenever I use it.
Currently having Lexus HQ follow up and contact the dealership manager - apparently there is no manager available until next week. Makes me wonder if that's why the standards have dropped, there's no one to check up on them...
So far, they have offered to compensate me for the window shades and played down the windscreen wiper fluid - I've told them I need it investigated properly as it could've done quite a bit of damage to to the car and contents. Will keep anyone interested posted.