Thanks for your help.
As far as i'm aware there both group 13. Surely though, if you can afford several grand for a car, another £100 a year on the insurance aught to be a fairly non-issue?
As for fuel economy if you can barely afford to run one, you aught to recalculate your fuel costs at around 20% lower than the official figures, as most users on the forum are only getting around mid 30's some upto around 40mpg on the diesel which is only about 10% more than people are getting on the petrols in practice, so if you find one for £1000 less used, it could end up cheaper and you'll have the better car at the end of it.
I think the 250 is group 14, and as iam 23 and coming off being a named driver to my own insurance, the difference seems to be significant with the quotes ive been given so far. I do need to look further into this though, and maybe i might be able to plump for the 250.
Problem is though, there doesnt seem to be many available at the dealers at around 13k with leather seats and satnav - the options i must have. Should i consider an independant/local garage, or is this a bad idea? I would prefer to get one from a lexus dealer but few are available and no doubt more expensive.