not true..
If you do the big bike license and are over 21 you can ride any cc/bhp of motorbike, if you are under 21 and only do the normal bike license you are restricted to 33bhp for 3 years.
I did my normal license 4 years ago, so am now entitled to drive any bhp bike
by the way .. just cause your restricted to 33bhp doesnt mean you cant have a 1000cc, you just have to get it restricted (which costs about 150 quid)