I am taking a group of around 30 sixth formers on a trip to the US in February - we will be flying from Manchester with British Airways but we have a 3 1/2 hour layover each way in T5 at Heathrow. I was initially going to allow the students to wander around the airport on their own and meet at the gate as soon as it was announced on the screens in the terminal but I was in T5 a few weeks ago and I didn't realise how big it actually is, or that most of the US flights depart a different building ('b' or 'c') than the one we will be arriving to ('a') so I was wondering what everyone's advice would be in this situation? Do I ask them to meet me at a pre-assigned point at a determined time or do I trust them to get the mono-rail to the other building all by themselves? Should I give them 'free' time at all or should I just make them wait in a seating area with me - or is that a big mean? Also, do you give them their boarding passes to keep or should I keep them and dole them out at the gate to prevent any from going 'missing'? Thank you in advance for your responses.