[Exim] unverified sender problem

Hi List.

I have a problem which I have not been able to solve.

A client of our sends us critical information from an oracle database via
an e-mail address which cannot be verified.

I, however, do not want to disable "require verify = sender" as this has
been working well for us.

They do not want to add a legit address or add the server to forward &
reverse DNS.

Is there a way to allow these mails through as they currently get rejected
due to adress verification failures.

the logs show H=domain.tld F=oracle@???. sender verify
failed.

How can I work around this?

Many thanks.

Tom