Perfectly correct.
The R33 GTS25t is P plate restricted, which means any P plater driving one is breaking the law. You could take it to court blah blah blah but you would be wasting your time. The law doesnt care about how old the engine is, how much the driver weighs, how much power you made at Joe Blows dyno.
Also, according to this law, a 1972ish 4.1L Cortina is P plate restricted, which proves the car doesnt necessarily need to be all that quick or powerful either.
If you're a P plater who drives an R33 GTS25t be prepared to be hassled, coz at the end of the day they have every right to.