Comment spam ramps up a notch

I'm not sure if moving to the new host is the reason, but I've had a lot of comment spam come through MovableType today (all of which was moderated) but annoyingly I couldn't permanently delete it as my computer did not have the new ip address for the domain name!
I have added another captcha, Comment challengeto our blogs. Hopefully it is not too difficult for you to answer the question correctly.