Ok so I've been tuning by ear pretty accurately for the last 2 years. But I've finally given in and decided to get a tuner.

I'm looking for one that can tune to open C, but all the ones I've looked at that specify which open tunings they support, don't mention open C. I'd rather be sure that it supported the tuning before I commited.

Also, mu budget has a max of £60. Anyone got any recommendations?

One with a metronone would be perfick!

Get the Boss TU-2 floor pedal. It is dead on accurate and very handy when you are playing live. Don't think it has the Metronome feature though.

The TU2 has no metronome unfortunately. In fact, most tuners don't have a metronome. If you want both, you'll probably have to go for multifx processors.
I've used the Boss TU2 myself, but I'm not really happy with it. It's pretty slow and not always 100% right. If you really want to use Boss, I'd go for the TU15, it's much more accurate. The only problem this tuner has, is that it does not have a direct bypass, so you will lose a bit of signal. (Note: I prefer NEVER to put a tuner between your guitar and amp).
These days I'm using a Planet Waves CT04. Very nice tuner; small, true bypass and very accurate. The Korg DT10 is also a nice tuner, so I've heard. I only use the DT7, because I play a guitar with Buzz Feiten System on it, and to this day, the Korg DT7 is the only tuner which tunes BFS.

get a tuner that has an arm rather than uses lights and stuff thats what i want