BA no longer think about an air bridge like they used to, it's all about quick turnarounds. You only use an air bridge at BHD depending on where you sit. When I have flown out the last few times with BA it has been in the back half of the aircraft so I've had to go downstairs and then brace outdoors and I definitely paid more than £40. I'm sure Swissport could supply a few air steps with roofs on them