[exim] Filter to archive inbound bcc messages

I use this filter to archive all inbound & outbound messages:
if ("$h_to:, $h_cc:, $h_bcc:, $h_Envelope-to:" contains "john@???")
then
unseen deliver "archive@???"
endif

if $sender_address: contains "john@???"
then
unseen deliver "archive@???"
endif


If I am listed in senders bcc, the message isn't forwarded to archive.
What am I doing wrong?

I suspect $h_Envelope-to: is erroneous, but cannot find a list of
acceptable header variables.

Thanks.