My first impression was that it's a rabbit or hare- possibly the folklorical hare in the moon, but wikipedia says it's a goat- and I suppose it is. But why a goat? And why is it upside down?
Here's what the church looks like from the outside. I love the weather-boarding on the tower.
And here's a view of the Thames, taken from the steps leading up to the private bridge that crosses to the private island. Yes, private. The bridge has a gate with a key pad on it.