It's OK I have found the answer in a dusty 1950's spectroscopy book which I found by luck stored in the wrong place in our library.

For anyone who ever wants to know this here is the answer..

The "r" means the energy of the states follows the order of the multiplicity once degeneracy is broken (regular or normal multiplicity). "i" means the order of the states is inverted.

i.e. for a ^{2}Π state you'll have Ω = 1/2 and 3/2.

Normal multiplicity would mean (I think) that Ω = 1/2 would be lower in energy with Inverted multiplicity being the other way round.