This is a transition. I predict they will switch over to the Euro completely in 2009.
id hate being stiffed with regards to £/Euro when buying something online, its bad enough some retailers are charging the same price for something even though the vat rate has gone down to 15% from 17.5% (and will no doubt rise in cost if/when it goes back up)
personally id be happy if the £/euro stayed at a constand 1:1, that way we in the uk might be tempted (or have it snuck in via the back door) to the euro providing that exchange rates with other currencies were also tied