I can not speak for the standard in England but here in the states playing the first two notes [Db] [Eb] up the octave and going back down to the [F] to finish out the scale is acceptable.
I wouldn't be opposed to someone playing the first four notes of the scale up the octave either but just as "basstrato" said, play the line out well and play it with conviction. That is what is most important.
I would, however, be prepared for the committee to ask for either option and have both practiced to a comfortable level just in case.
Good Luck Man!