Davep,. . Just been for my class 1 , BMI is not a factor in them isuing a class 1 yet as already has been said.
With regards to the waiting time for getting an appointment i rang up on Friday last week and got an 0830 appointment for the following Monday , because apparently the afternoon time is more popular so there is a waiting period for them.So if you don't mind getting up early and want to miss the waiting then book an am slot.
hope this helps.