You are very close flopsymopsy.

Hmmm... a holder for a receptacle, lol, that should be a wide enough description.

Where a sliding gate fits into?

So many people are close that I'll post a picture of the whole item when I get back home later today

Big street flower pot?

Y

You have it, ysmay! That is exactly what it is, though there are no flowers actually growing yet this year. It's more like a big ashtray at the moment

and the next subject is ......... ?

A metal roof?

A beach chair?

Would you believe that it is supposed to represent a tree. Frankly it looks like a cross between a giraffe and a kangaroo. But whatever, it is a complete waste of money and a bit of a local joke. I can think of a thousand things that would be much better than this eyesore.....Mommakat

For those of you who are confused by the previous post, Mommakat is referring to the photo I posted last year about the sculpture at the Mandurah bus/train station.

No, not a roof, nor a beach chair - nor even an Australian sculpture
I'll let this run a bit longer, before providing the answer.

Curtains?

Metal building siding?

Not curtains, nor a building siding - though it is associated with a building.
Clue: the blue is simply a reflection of the sky

A garage door?

Not a garage door either. The reflected blue sky is a subtle hint

Conservatory blinds?

Part of a solar panel?

A tin roof? (Was my first thought but thought it was too obvious.)

trangie has it, so well done
Here's the whole thing:-

It's on the roof of our house, and provides most of our hot water!

Seen outside the U.S Embassy in London today; OK they're State flags, but how many can you recognise?

Delaware
Michigan
New Jersey
Georgia
Connecticut
Massachusetts
Maryland

Maybe... ?

Nearly, but not quite right; well done anyway. As there aren't any more attempts, here's the correct answer from left to right:
Delaware - Pennsylvania - New Jersey - Georgia - Connecticut - Massachusetts - Maryland - South Carolina.
Admittedly spotting South Carolina is very difficult on this image, but look closely and you can just about see part of the white crescent in the upper hoist canton of the flag.
Michigan and Pennsylvania have similar flags, but the former depicts an elk and a moose each side of the central shield, whereas the flag of Pennsylvania has prancing horses.

As an aside, when I poked my camera through the embassy fence, to take this photo, I was immediately approached by an armed policemen! He was very friendly though , when I showed him the 'innocent' photo I'd taken - one advantage of digital cameras

I didn't know that individual states had flags until I joined FT so this site is definitely educational.

I spent some time in front of that embassy in my youth, or nearby anyway... only we weren't holding flags but placards!