Thing is, looking at the prices via Google, it doesn't look like most companies are even taking note of the higher price. I think what this might really be about is reducing the loss-margin when selling to retailers.
For example, if your RRP is 55 quid, then you can add about 5 pounds to the market price of your goods by saying that the high RRP means more profit to the retailer. The retailer, however, knows that the game will certainly be in demand, but knows that pricing it at 15-20 pounds above everything else will pretty much isolate it from a fair segment of the market. So the retailer absorbs the extra price, and makes slightly less of a profit, but doesn't lose sales.
You can pre-order the game for about 35 pounds on quite a few sites in the UK.