Booked in 1st on flight from IAD to LHR then on to Barcelona in biz class. With 3+ hours in LHR, which lounge are we entitled to use. The info on the BA site is a bit confusing. The first bullet point looks like it would be the biz class lounge, the second looks like it would be the 1st class lounge. Looks like we arrive Terminal 5 and depart Terminal 3. First and Business Class customers connecting on the same day of travel, or before 6am the following day, can access the lounge when travelling between an international long haul (a oneworld international long haul flight is defined as an international flight marketed and operated by any oneworld carrier with a scheduled flight time longer than 5 hours) and an international short haul or domestic flight (and vice-versa). Lounge access will be determined on the international long haul ticketed flight (either First of Business Class) regardless of the ticketed class of travel on the international short haul or domestic flight.