good spec...if it was me i'd ditch park assist and use that £££ towards fully electric memory seat option. i am biased though as that's exactly what i did. for me the fully electric seat with driver memory is used much more regularly than park assist ever would be, invaluable when both you and the wife are using the car i used to spend days having to try and get the seat/wheel back just how i liked them, with memory function its simple
...but then i don't live in london so maybe park assist more useful for you???