How to reg a 125 reg as a 50 back to a 125 reg

Soon i am looking to get a piaggio typhoon or a gilera runner 125
I have seen some nice ones but they are registered as 50's and i would want to register it as a 125 to make it legal etc
Can you do this if so how?

 

on the logbook change the cylinder capacity to 125 and it should be fine. it usually only has to go for an inspection when your trying to lower the engine size due to it making insurance cheaper etc.

 

oh right thank you, so maybe if your raising it it may not have to me inspected