QUOTE(2Bdecided)
If you don't get a reply here, try at the Monkey's Audio forums. Matt (the creater of Monkey's audio) is well aware of replay gain.
I posted there a few week's back but still no reply, apart from Destroid agreeing with me. Searching back through the Monkey's forum there are some previous posts which indicate that Matt's view is that Replaygain is the domain of the player, not the format. Which means that the Winamp plugin would be the way to go.
QUOTE(amano)
Unfortunately there is a drawback with this plugin which is that it only supports Track Replaygain, not Album. Not only that, from my quick scan through the readme I get the impression that for other formats for which Album Replaygain is supported in Winamp, this plugin will still force the output back to Track Replaygain:
QUOTE(dsp_replaygain.txt)
However, if the Vorbis file has a RG_AUDIOPHILE tag and you have enabled Audio-
phile support in in_vorbis, the gain calculated by the plugin will bring the
file down to "radio" Replay Gain.
I have found a way round my main issue with using FLAC. So in the end, despite my initial request to not suggest I use it, I have decided to abandon Monkey's and go with FLAC

. Monkey's simply doesn't allow me to use Replaygain exactly as I want it.
Thanks everybody for your help.
Tim.