I don't do the Thames radar sectors, but the best way to understand it would be to trundle down and visit us. It's a lot easier to explain when you're sat in front of a radar screen and we can show you why you end up where you are.
I appreciate if you're based in Southend it's a bit of a hike, but have a look at the thread in Rumours and News about coming down for Truce training and you might well get the petrol paid....and lunch....after a fashion.