[Exim] wildlsearch problem

Hi,

I'm trying this in my RCPT ACL:

  deny  sender_domains = wildlsearch;/etc/exim/blocked-sender-domains
        message = domain ${domain:$sender_address} explicitly blacklisted\n\
          ${lookup{${domain:$sender_address}}wildlsearch{/etc/exim/blocked-sender-domains}}\n\
          please mail abuse@REAL_DOMAIN if you think we should unblock you

..with /etc/exim/blocked-sender-domains containing lines such as:

^mail\d+\.recessionspecials\.com: you don't accept our bounces
123-malls.com: you don't accept our bounces

Now lines which aren't regexes work exactly as I'd like. Presumably I've
missed Something Stupid in the regex case. Is ":" the Right Delimiter?

Cheers,

Matt