There is a drain away in the lane and that needed to be unblocked and the pot cleared of the debris in it.
First we had the locate the drain under the build up of soil and gravel over it.
We then had the problem of lifting the grill which was stuck fast and took a good twenty mins to release.
The pot was then removed and the container cleaned out removing all the sludge from it.
The gravel was replaced in the lane and the waste removed. It took almost one wheelbarrow load to do so.