The !battle command in the 0.8.1 branch is roughly the same as it was back in the 0.7 days, and I don't think it ever really worked.
I don't know if Kilm made too many changes in his branch to prevent older plug-ins from working, but you could temporarily move aside your vh_Towers.cs file and try mine:
https://bitbucket.org/Llie/vhabot_plugins_default/raw/5ad13d3cedb8f51d92786b2e26b530d3c78c1635/vh_Towers.cs