Unless they've changed it, that's not the case, Tom.
Certainly when I did it you could indeed only get A* at A2, but it relied on 90%
on the A2 modules and an A overall. So you actually needed
less in your first year*. I'd check the rules on that - it's not at all unlikely that they've changed, but that's not how it worked when I did it.
*Which leads to the odd thing of subjects potentially being your best AND worst, as was the case with me in History. 100% in first year, 89.5% in second year. Best total mark, only one I didn't get an A* on.