As far as I know, it's the pond itself - however,as I said before, it has leaked for years and past attempts to stem the flow have been fruitless. They worked on it about a year or two ago, when they completely relined it with a new covering of clay (which also gave it a very sureal green tint!!).

All seemed to be well for a while, the Duck House and the Ducks returned, and all appeared hunky-dorey. Unbeknown to us, was the fact that it was still leaking and was running the risk of contaminating surrounding areas, including the natural spring that is there.

So as far as I can gather the "listed" pond, the facia, was to be removed, the edge was to be breeze blocked and polythened, the original rocks replaced "as was", remortared, and the base re-clayed. Thus producing a "listed", original and natural looking feature that has been there for years (just with some modern techniques employed underneath and unseen, to help it cope with the demands of 21st century!!).

So really, in that respect, it's the concept that is "listed". I guess that English Heritage need to be reassured that regardless of how it has been repaired, the "Outside look and feel" will be as they were before they started the work.

I'll have a chat with one of the blokes who has been working on it next week hopefully.