Plus you don't/can't earn ZE1 points in the UK either - instead all you can get is a few airmiles per rental. I suspect it is as the insurance costs in Europe are significant portion of a rental's cost, with a very different system to the USA, as everyone pretty much has to buy insurance from the car company, rather than getting it from our credit cards.

Btw: As another FYI; your presidents circle 'gaurenteed' upgrade in the UK is only valid at airport locations.... which means you need to pay an airport surcharge to have a better car. As a UK based Presidents Circle member (though admitadly renting on hugely discounted corporate rates as I work for a very big corporation) I rarely get upgrades outside of an airport location, and even at the airports it can be a bit hit-and-miss until I start being a regular there.