BP-Scholar - How to change group avatar size

Hi guys, I'm using a child theme of BP-scholar 2.4, and have just set-up my first group forum.

The one thing I notice though is that with the size of the group avatar at 150px square you have to really scroll down the page to get to see anything.

So I was wondering if you could tell me where I need to go to - or what css I need to add to change the size, as it looks like it gets hard coded somewhere rather than in the css.

Hoping its a setting somewhere thats just eluding me!!!???

Thanks guys