Ophinky, When did you inform the letting agency about this? On first contact by phone or email, or did you wait until you met in person?
Basically, I'm wondering if letting agents prefer cash/certified cheques up front and if having to inovice the employer is seen as a hassle that slows down the process. I only have two weeks to find a place, so a little neurotic. But, from the responses here, it doesn't seem like I have to worry!