Jb, i would like to correct you ... As per the current rules, part 1 plus 5k gives u an rtr(c) for 20 years and 10k will get u a lifetime one.
I got mine renewed last month and was a fool to listen to my company chaps who said that that i could get only a validity of 3 years even if i paid 10k.
I paid 5, i got 20 .....