It seems that everyone on here bought at a huge discount (I certainly did), so that is presumably what shot it to the top.
I asked MG for a 4 Trophy LR, which they were happy to sell me for £32k, but offered me an S5 Trophy LR for £24k, so obviously I bought it (sight unseen).
So I can't see it as being such a victory for the S5 given the massive discounting.