Peter, you would have the absolute minimum that is legally required once you'd finished your flight training. Will that get you a job in the current environment? No.
If you want to fly an airliner from the get go, you pretty much have to be on a tagged airline scheme. A levels are not generally not enough to get a spot on those. Most candidates have a degree. It is not enough to do an integrated course, you need to be on a tagged one.
If you want a different career, you'll definitely need more than A levels.
Have a look at T&E and the Wannabe forums.
Good luck, to survive in this industry, you'll need tenacity and luck.