Ok last thing to decide on, I do use mine off road a bit. Is the diff a physical one stage lock or is it electrical clutches, is it driver operated with a switch or does the car make up its own mind, in short is it worth 450 quid? letters not necessarily in the right order

It's variably electronically controlled and not user-selectable. First time you get stuck without it you'll be wondering if you wouldn't have with it, and when you don't get stuck you'll be pleased you saved the money.

Should also make some (small) difference on the road.

Thanks, on the tractors, wheel spinning, engage lock and off you go, if it is totally anonymous I will always think I wasted the cash and that I am a driving god. letters not necessarily in the right order

Buying new it's definitely worth £450, but buying used it doesn't matter. You will be able to drive same places but with the diff it will be more smooth and with less fuss. Not all anonymous, if you have the diff view on the screen you will see when it locks up  Supporter and maintainer of EDF - Mrs Edfors' shopping cart.

My 2013 brochure says this option aids the cornering ability of the V8 models (not available on V6), if thats correct then yes worth £450, get every extra possible to help this thing drive better

You're flogging a dead horse, Carlos - sell it and move on.

I have to stick with it so am going to put some of the £10k loss I would see if selling into some wheels, stealth pack, DMS remap and fingers and toes crossed that a few replacement suspension parts will make it feel more stable such that I can enjoy it more.

I don't have this option but does the active diff improve the cornering stability as per the narrative in my sales brochure?

Not stability as such, but you would expect a locking diff to tighten the line under power by sending torque to the wheel with more traction.

Wonder if the L405 will ever get the L494's torque vectoring.

And its suspension