Thanks all. It's the greyest shade of green I've ever seen, but the original service book and DVLA both agree with Lexus and call it green so who am I to argue....
It successfully brought me into work today, the only issue being a brief period of time when the temperature would adjust up but not down (soon resolved itself) and the instrument display brightness fluctuating slightly until I turned it up to fully bright. I think a detailed mechanical inspection would reveal all sorts of problems, but for now I'm going to enjoy the fact I can buy something so accomplished for so little money.
One important bit of work done was to remove those graphics on the front and rear screens - my children happily got stuck in on that job.
It's interesting to compare its size with my 2010 Avensis. I haven't parked them side-by-side yet so can't say on length, but the Lexus appears to be no wider across the mirrors (we have a tight entrance into the office car park so I'm conscious of this) and offers very little increase in legroom over the Avensis, yet it still looks much more imposing. Surpised to find the rear seats don't fold down (was used to that on my Camry saloons, quite a handy feature). Not as much headroom as I'd imagine, I like to sit quite high in a car but am finding the sunroof limits things a bit.
I suspect I'll be finding toys for some time. I couldn't fathom out how to raise the seatbelt mount on the pillar until my daughter pointed out the switch on the door. The electric window switches are rather familiar however, just the same as in my Camrys and I was surpised to see it only has one-shot operation on the driver's side down movement. Even my 1980 Datsun has one-shot up and down.
I'm finding that judging the position of the back end when reversing is not easy, the body tapers in and there's nothing much visible in the mirrors. Happily so far I've over-estimated and had a few feet spare. I think I've got too used to the camera on my Avensis...
Edit: Why do some Mk3's have clear front indicators and some orange? I wonder if mine were originally the latter but have been changed as a modification/result of accident damage. I noticed the screw was orange. This unit seems to be in two parts, is the rearmost bit a marker light in some countries?