This morning I finally got around to raising the ride height (been a little distracted recently) and can't wait to go for a run.  The adjustment was very easy, even for a workshop novice like myself.
 
 It needed doing, it was set to the lowest ride height possible.  The previous owner must have been short.  The rear tyre now is just a little clear of the ground when on the stand.
 
 I'll let you know if it feels different.