RE: Parking, I understand that parking facilities at Cranebank are strictly limited and you are advised AGAINST taking your car there.
What I would suggest, though, is trying to make your own way on public transport to training on the first day and ask your trainer about using other British Airways staff car parks. Of course, from there you'll be able to get a BA(X) shuttle bus to Cranebank.
Imagine you'll be issued with a BA pass immediately, so you should have access to parking etc.