Originally Posted by
BA6501
OP, if you were to miss it there are plenty of flights after the 15:45ish IB service - something like a 16:30 and a 17:05, normally, then a LGW flight and 3 BA flights.
Even easier, as you just have to walk about 1.1km in a more or less straight line to your next gate. Get off at the extreme South end of the building, show your passport, and walk all the way up to the high K gates. No security. Bags should be fine.
Record!