Tried to register yesterday, but all the captcha images were illegible, and I ran out of retries looking for one that I could work out the characters on! Found one that was legible on the third attempt today.

Yea sorry about that.
This captcha like most can be damn hard to read.
Plus I lowered the retry limit thinking it might help reduce some of the automated spammers we've had here recently.
Apparently the captcha isn't to hard for the bots, and, or they have some way to exploit around it.

I need to upgrade to the latest version of phpBB then probably use an additional anti-spam-bot mod that asks some questions or something beyond just the captcha (that could be set to be more readable).
Just been putting it off a little because it will mean a fair amount of work porting over the theme plus mods, etc.
Maybe this week some time..

Update:
I did install the latest phpBB a few weeks ago.
Even using an easier CAPTCHA haven't seen a spammer since.
Although "View active topics" broke in the update process.