Sorry to tell you mate but the reply you will get from BA is;
"all work experience placements have been suspended"
The same is true of all other UK Airlines. It's a pity, I know and perhaps when recruitment picks up in a few years time they will change their minds.
Your best option however, would be to target Airport Operating authorities. Like write to BAA and try and some experience with them around Gatwick. Youd get to see the whole airport; runway inspections, control tower, oversee aircraft turnaround etc...
From the post above I know of friends in the past in 2000/2001 who got similar deals but 9/11 changed all that.