Dear all,
Thought you might be interested in this one...
http://7timer.y234.cn/V3/product.php?language=en&product_id=1&country=UK&adm=UKG6&site=0It gives you a seeing prediction hour-by-hour (see attached) for the next 60 hours or so. So far quite accurate.
I like this one because apart from its accuracy it is clear and concise and includes all the important bits we need. Oh and its free.
Now if only someone could come up with a piece of software that allows you to define the seeing conditions and then they happen!

Cheers,
Mark