Hi aviatorvette,
This RTR(P) (permit) is valid for 3 years initially and can be renewed subsequently.
According to the latest circular by WPC, you can now apply for a 10 year or life time permit.
You will not face any problems in your conversion with this permit.
Actually, most people confuse RTR(P), RTR(C) and RTR(A) as being the same thing.
RTR(A) = The actual Indian RT .. aka COP RTR(Aero)
RTR(P) = COP RTR(P) .. aka Permit based on candidate possessing valid commonwealth CPL and RT
RTR(C) = permit issued to candidate on the basis of having a commonwealth RT only (no CPL from that commonwealth country) and having cleared part 1 exam of WPC.