Multisite SSL not working on Marketpress site

Hi,

We have installed marketpress and hired a developer from your jobs section to write our custom gateway plugin. We have managed to get it all working perfect on tatestau.com however having problems with tri-alliance.com.au

Currently we've tested that the problem is related to SSL on one our sites. (the main blog site). ie
https://tri-alliance.com.au wont work, redirect loop
https://vic.tri-alliance.com.au which is a subsite works with https (few design errors but no redirect loops).
Our main site ssl does work an example of this is this image https://tri-alliance.com.au/wp-content/themes/trialliancemain/images/tri-header-logo.png

I have looked across the net, asked our gateway developer who's quite savy with custom plugins and neither of us can figure out what is wrong here.

Does anyone have any advise to how we can fix this issue as its the major thing that's stopping us move forward with Marketpress (as our gateway requires that its return link is https)

Thanks,
Billy