Tightened spam checks

Hi all,

Due to the recent spam, I have tightened up some of the spam checks to be more restrictive. All of the spammy posts where flagged by the system but the thresholds where set too high to actually do anything about them, unfortunately leading to them appearing on the site.

If you get any issues with it flagging your own posts, let me know, but I think it should be better now.

Regards