Flight Level, Transition Layer and when to use it

[Gertrude the Wombat]

Like I say, I never fly FL due to being VFR

Asked by ATC what level I was aiming at, VFR over East Anglia on a day with infinite visibility, I said "FL95" (instead of the "3000'" or so they were expecting), resulting in a giggle and a "remain clear of controlled airspace".