It really depends on the specifics of your own booking, there isn’t a fixed answer. If it’s a simple booking (note - BA’s/Amadeus’s definition, not yours), arranged before 6pm UK time, it’ll be processed the same day and back to you within however long it takes your card company to handle it. If it’s a complex booking that requires manual handling, it’ll go into a queue for processing. Mostly these are sorted within a fortnight, but there are some that take a bit longer.