The Greenwich Park Bowl?

Fin writes:

I was walking in Greenwich Park today and came across a circular fenced-off area in the south-west corner, just north of the tennis courts. It had a rusty iron fence around it and a locked gate with signs that said 'Hazard - Keep Out'. Naturally curiosity got the better of me and i climbed in, to find a large raised area of grass like an inverted bowl. Steps ran up one side and joined an overgrown row of paving slabs running along the centre of the bowl, with some sort of metal grill right in the centre. This 'path' was also lined with what looked like those hook-shaped ventilation pipes you get on ships. I didn't venture far in case the ground gave way or something, but I am most intrigued. Can you or your readers enlighten me as to what this area is, or was? Unfortunately i didn't have a camera on me otherwise I'd send you a picture.

The Phantom replies:

What is this - Greenwich Enigma Day or something? This seems almost as much of a mystery as Miss Mott.

There is so much to be discovered in that seemingly tiny patch we call Greenwich Park that it doesn't surprise me that there's something new and hitherto undiscovered somewhere off the beaten track. I vaguely know where you're talking about, I think. I wonder - is it in line with the red brick building that's part of the underground water system? It could be part of the notorious tunnels in Greenwich Park which date back several hundred years (see The Greenwich Phantom: Tunnels in Greenwich Park ) but it sounds too recent to really be connected with it. Given the way that the land seems to cave in at a moment's notice round here you were probably wise not to tread any further. It does sound like a reservoir. Something banging at the back of my brain tells me that Greenwich University did some low-level experiments in the park way back, but I thought it was all cleared away. Actually, I may be completely wrong; thinking about it, it could have been the Peninsula. Or somewhere else entirely.

Basically what I'm saying is that I don't know. I'm hoping that someone from the Friends of Greenwich Park will read this and be able to tell you. In the meanwhile, I'll do a spot of digging (not literal.) Watch this space.

When is someone going to write a really in-depth topographical study of Greenwich Park? Or is there already one that I don't know about?

Incidentally, folks, I'm sure Fin wouldn't mind my telling you about his own website that he 'accidentally' left the address of on the bottom of his mail. He's a local playwright and poet and you can find him here http://www.finkennedy.co.uk/