My last Speed Awareness course was for a 37 in a 30... coming off a dual carriageway on to a 2-lane in a "built-up but quiet" area, i.e., industrial units / swimming pool / out-of-town shops... well past midnight as I was coming home from band practise, and I ended up on the course with tools who were hurtling past schools at 60mph and laughing about it... in all honesty I paid attention and it did make me a better driver as far as "projecting ahead" while driving, and glad I did it.
54 in 30? 3 points and a £60 fine I would wager, but don't rule out SAC.