Luke,
Everyones answered your clutch question so I won't bother however I would question your choice. In England you'll find the roads crowded, particularly in the south, there's a lot of stop/starting. For this reason my wife and I both drive auto's, for you it has the added advantages of not continually trying to change gear with the door handle! (a problem I had the first time I drove a left hander) and being able to concentrate more on what the fool in front of you is doing (and there are plenty of them) leading to a less stressful holiday. There can also be a bonus, the hire companies here don't have a lot of small auto's so even though you book a small car they will often upgrade you as they don't have the small one available, it's worked nearly every time for me and I've booked a hell of a lot of cars!
I hope you have an enjoyable visit and if you visit Harrogate look out for a lifted red VX, it'll definately be me as it's the only one.
Rgds Col