I just enabled this trick to kill spambot registrations on a phpbb board I admin. I know invision uses a similar structure to phpbb, so it might work for you guys too.

http://www.phpbb.com/kb/article/custom-pro...i-spammer-tool/

It seems the reason the Haven got the shit spammed out of it is because recaptcha was finally cracked late last year and spammers were having a field day.

Seems feasible, though mostly Lotus has handled the forum software management. I'll try to see if I can give this a shot at some point.