No Theory Test but what I know BBDC got a complusary Theory
lesson (only 1 lesson) you must take before you can book for your
TP. Not sure about the other Driving Centres
Also, if you got the time try to take in the mornings or afternoons
(Off-peak hours). Firstly, no much vehicles in circuit and also
smaller lesson group so instructors got more time to pay more
attention to you. Lastly, not so expensive!!! 
I took started my lessons in mid feb this year got me lic in early
April. 1 time pass. 2 points only!!! I don't even believe
myself!
Lessons is just like your 2B but got additional bumpy course.
Longer route in the Circuit.
Because you already have 2B, TP now look for your traffice rules,
road confidence and your handling of a larger class bikes (or so I
heard....). Should not be a problem unless you did not ride since
you got your 2B. Maybe then you need more additional
pratice!!
Good luck! 