U've never used 5th gear!!!!!?!?!?!?!?!?!?!?!? You POOR boy, mind u, (presuming by the name) living in london i suppose i aint suprise, u should be able to hear by the tone of the engine, if ur in 4th and the car souds like its struggling, (or the reeve counter is at 3000 as average guide) change in to 5th for speeds of about 40mph plus, but never go in 5th in 40 mph or below speed restricted areas. How come ur doing test but never used it? doesnt sound like u have had much experiance at going a decent speed. There again, i am a mere country girl in the north who loves driving/speed. Im a better driver at higher speed and my test is in 5 weeks.
Gd luck all the same!
(using 5th gear at 40/50 mph uses less fuel and doesnt hurt the engine in your car so much. DONT HURT IT, THAT IS NOT NICE. love the car, and treat it as if it was a lass, unlike me, who treats her lil'pug lovingly but a little harsh from time to time)