Which Service is Best to Grab and Expiring .co.uk Domain Name?

I have never managed to secure an expiring domain before although I have tried with a few .com's using pool.com but I don't think it works very well.

I have my eye on a couple of .co.uk domains that are expiring shortly. Which service or services are most recommended for grabbing that domain?

Ideally it will be free until the domain is secured.

 

not sure about co.uk specifically, but snapnames was always the best for me