Depends what company/contract you are working for.
I transfered my SC from the MOD to Home Office, but the Met Police do not recognise/accept MOD clearences.
It took 3 months to get additional clearence for the Met Police just for CTC even though i'm SC for MOD & Home Office.
DV,SC & CTC are also only valid for a certain number of years and need to be renewed. You may find that you are now out of date and have to go through the whole process of form filling again...