Hi Phil,
Not at all
There are a couple of ways you can approach this problem, as far as I can see:
Depending on the level of interaction between this site and others, that you might require, you could try setting up say, Opera or Firefox with the home page set to the grid finder site, and use it as a single purpose browser, almost like an app. This is, of course, after upgrading your Safari plugins and extensions*, and providing it still doesn't work correctly for you. You'll find both Opera and Firefox in your AppStore and they are free.
You might want to consider upgrading your system to OS X Mavericks (10.9), which will bring an updated version of Safari, that appears to be working fine with the site, as shown in my screenshot. Again, the upgrade is free and I cannot recommend it highly enough: Mavericks is just great (my MBP is nearly four years old, and I have a number of Linux apps running, so it wasn't an easy decision, but really glad I did go for it).
* I'd start with the
Flash player plugin - make sure you have an up-to-date version - at least 13.0.0.206, the latest is ...214, otherwise Safari might be blocking some code, for your own protection.