Depends how you drive, i managed 412 in mine standard with 2 passengers and stuff in the boot. R27 with 1st style gearbox with shortest 6th gear. Think i was between 60-70 for most of it. Was on a long run. Never managed it since tho lol!
But the Clio will hate you.. She was made to be driven, built by the hands of craftsmen to be thrapped. Her DNA means she was born and nurtured to be used, to have her go pedal pressed flat to the floor....
Would it not be better to do the journey and see how many times you can empty the tank, that would be much more fun.
Drove like a pensioner on way there.... three quarters of a tank! Averaged 27.6mpg! Drove back normally between 80 and 90 and got 29.9mpg and just under half a tank