Ok, it's not easy getting a photo of the bottom of an A2, so forgive the following image, which is a fairly well known picture of an unfortunate A2 accident, where the car flipped on its side - nobody hurt and I believe the car was repaired, so all ended well.
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The yellow arrows show the official jacking points - in a garage situation, the plastic bungs are removed and then the arms of the lift will locate into the holes, no matter whether it's a 2 post or 4 post lift. You can safely use these points with a standard workshop jack (not the one included in the A2 tool kit) - if you can fit the proper "top hat" adapter, even better.
The blue arrows then show safe places to put axel stands for safe working.
Areas shaded in red and not safe at all - these are only very thin (1mm) aluminium panels and any attempt to jack in these places will see the jack punch through with no resistance at all. Same goes for all the areas that are black - these are the engine under tray, side sills, fuel tank and boot tray. All are made from plastic and all are totally non-load-bearing. I've seen plenty of A2s with cracked sills from garages who put jacks in this area - there is metal underneath that will support the car, but there's a gap between the plastic sill and the metal, so the plastic squashes and cracks.