All will hopefully be sorted this coming weekend. MOSFET reg/rec and stator have been ordered from RO. Might use the new battery now just to eliminate the last possibility, but I'm still not completely convinced it is part of the issue.

Can't see in the post - where is the new rr that you tested in it from? I had an issue with a cheap Chinese one that would sometimes randomly cut out completely, possibly poor soldering or something within the unit? Sounds like the rr is bang on the problem though

Do not know where the seller got it from, but it was from eBay. I have one that seems to have died completely, and one that is intermittent. Off the top of my head, I think the iffy one is this one (from Nov 2012):

http://www.ebay.co.uk/itm/For-Honda-RVF ... 23214053ac (Cheaper than when I got it at £34.95!!)

And the dead one is this one I got in March 2011:

http://www.ebay.co.uk/itm/HONDA-firebla ... 461a992560 (cheaper than when I got it at £30!!!)

I will check at the weekend, but I think that's the right way around. To be fair to both sellers, it may be something other than the quality of the reg/rec that has caused both to die in a relatively short timescale. Previously, the bike was fitted with a genuine Honda replacement finned item by a previous owner a year or two before I got it, and that did an entire decade!

That's the exact one I bought back then (2011) too :-) new battery would be good to use just to not put any pressure on anything :-) good luck

replacing the standard reg/rectifier with a mosfet one is certainly the way to go !
i fitted an 07 onwards cbr600rr mosfet unit on my other halfs nc23, replaced the wires to the stator with much thicker items doing away with two crusty/burnt honda connectors in the process and wired the charge wires straight to the battery,
before the conversion i was getting a max of 12.2 volts across the battery, im now getting 14.6 volts at idle and staying constant as you rev it.
seems the sh type does funny thing when it gets hot and it does tend to get hot while the mosfet stays cool.