After another "wonderful" afternoon trying to get my head around this, I've actually found that each site_config file doesn't actually work, even though they are configured as per the instructions. I REALLY need a fresh pair of eyes to look at this guys........so if anyone feels like a challenge (and I'm sure it'll take someone apart 10 secs to resolve!), I'm happy to give someone admin access/ftp access etc and pay them for their time......its actually got to the stage where I simply need a small nudge in the right direction and I'll be fine........
So if anyone wants to make a few bucks (payable via PayPal) PLEASE LET ME KNOW ASAP :-)
Many thanks