[Exim] System filtering on recipient addresses

I'm having some troubles filtering on recipient addresses under exim 3.22.

What is required it to blackhole all incoming mail with a local part
matching ABC{10 digits}.

The following conditionals have failed to catch it:

if $recipients contains
abc[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]@
if $h_envelope-to: begins
abc[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]
if $h_To: contains abc[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]@
if $local_part begins abc[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]
if $original_local_part begins
abc[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]

I know abc[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9] is reasonably
sound as I have tested it in a personal filter.

I've tried using the likely looking and a few of the unlikely looking
variables in the book...

Any ideas?

--
David Bretton
Core Systems Administrator (Mail)
Energis Squared