Steyning Bostal is Strava measured at 0.9 miles long, with an elevation of 407ft.
Of the 10 geeks that have ridden it:-
The quickest is 6:11
The slowest is 8:06
(I couldn't be much more in the middle if I tried)
Only 10 geeks? You can add a runner ex tri then. I did it 7 years back when training for the Caledonian Etape. Had to wait 6 weeks into training before I had the guts to try it with my compact chain set. It was ok in the end but didn't time it.