Help needed for group avatars in BlogsMU

I posted something along these lines on the tail-end of another post question. I need to find out if and how to make the changes to the default avatar in Buddypress theme Blogsmu ripple through to all uses of group avatars in the site theme.

At the moment I have uses Sarah Gooding recommended functions.php update (https://premium.wpmudev.org/blog/how-to-add-a-custom-default-avatar-for-buddypress-members-and-groups/) to the child theme to set a new default avatar.

It has changed the display of the group avatar to the new default in the group directory and group details but the theme displays a widget of random groups which still show the old avatar.

I have opened up the site for viewing http://artsblurt.com/groups/third-test-group-889600580/

In addition to this when a new member creates a group they are presented with the old avatar as a default. I think I need to make deeper changes to affect the entire theme - or BP core itself. I am not sure how to go about this in the right way.

Can anyone help please?