Thanks for the replies.
I haven't completely ruled out SFX, I tried it a while back when Konica was available and I much preferred the Konica film, it was very fine grain and thus gave amazing portraits and figure studies (the eyes looked pretty wierd, but it did wonderful things to skin!) SFX isn't really a grainy film in 120 - it is based on HP5+ I believe, but it didn't give me the same silky smooth effect. Maybe if I worked at it - different filtration, developement in Perceptol stock or something.
But as you can gather from the fact I haven't yet used up all my Konica rolls that IR was only ever something to play with occassionally, no big deal (we don't get enough of the right weather in the UK!)
The Rollei films look interesting, I'll price them up and see it they're worth a play.