Hi Perry,
There are many seawatching points and all will produce a very good movement of seabirds in the right conditions. In Spring Dungeness will be the best and probably the only site worthy of a visit, with smaller numbers of the same species from Copt Point or St Margarets Bay. In the Autumn the North coast comes into play and the hotspots are Shellness Point on the Isle of Sheppey, Reculver and the headland at North Foreland and Foreness Point. I must admit a passion for seawatching and have seen some really great movements over the last twenty seven years or so, it's very challenging and is an not for everyone. In August, in a good, all day movement it's possible to do a fourteen hour seawatch:eek!:
As for conditions it is to complicated to go into fully but in the Autumn a stiff wind from between North West and East should be sought after, but you can get perfect weather but no birds.
I have recently moved to Thanet about five minutes walk from Foreness Point so will be seawatching from there this year. If you come to Thanet for some seawatching in the Autumn I would be willing to meet up with you and point you in the right direction:t:
Regards,
Barry.