Hey topper
I very much doubt that you need any luck. Yuo seem to be a good guy and probably a good pilot. If BT are as short of staff as I have heard and flying eagle said, I seriously doubt that they would fail anybody that don't screw up BIG times. Just go there, relax and be your self. I do realize that you are desperate for a job and desperate are the worst thing you can be on an interview. There for, to suceed, try to think of all the bad stuff instead of the good stuff. Sounds strange, I know, but it actually helps.
Go get them tiger