Paul, not too sure how it panned out with LH and DL. UA do not have E ticketing facilities with BA for interline travel, however, we are able to purchase ZED tickets online via Lime Management, there is a small fee, Lime Management also runs the product for our BA Travelcards for duty travel, again a fee, but it's duty travel, so claimed back. We had to enroll to use the service for pleasure travel, but had access within 24 hours. Not sure how it works in reverse for BA staff travelling on UA, but we are still accepting paper tickets for Interline travel, so probably it's status quo for BA.