Essex Walking

Any good walking were dogs can be let off lead and their is no livestock to encounter within Essex?

I live near Southend on sea and often use Gunners Park and the beach bellow when the tide is out. I have also used Hocklywoods, Priory Park and South Church and Two Tree Island in Leigh.

I would be looking for places along the Fenchurch Line as it leaves from Shoeburyness or within easy reach of a bus. Can't go anywhere by car at the moment as mums broken her toe!

Places close to public transport are best!