My wife and I will be flying from Ottawa to London Heathrow via Air Canada in May 2014 and then connecting to British Airways to fly on to Edinburgh (and the reverse when we return to Canada in early June). I booked the first flight segment with AC using Aeroplan points and booked the second leg to Edinburgh with BA - so two sets of tickets (and, as I understand it, additional problems if the first part of our trip is late and/or we cannot make the connection). We will need to pick up our bags at LHR T3 and take them to T5 to catch our BA flight as they cannot be checked right through to our destination. I allowed almost 3 1/2 hours between flights (coming and going) and thought that would be enough, but an AC agent suggested that she would have allowed more time just to be on the (really) safe side (i.e. 5 hours).She also noted that there could be flight schedule changes between now and when we fly. Your best advice on whether we have enough time to transfer terminals and catch our flights, and whether or not I should change our times to allow more of a buffer, would be much appreciated. Thanks.