Drainage inspection chamber

[Bogart]

Whilst messing about trying to find the location of my underground pipw leak, still ongoing, I decided to have a look at my drainage chamber.
A right mess it is. The chamber is 480mm diameter and is covered by a rotten lid of 620mm x 480mm. As you can see from the attached piccy
the lid is the same size on one side 480mm as the chamber diameter itself. Finding the lid rotted and bits inside the chamber thought oh will get a new lid.
Problem is I cannot find a lid this size. nor can I find a chamber of 480mm diameter either. I may point out that the whoile thing is hidden awau under a patio slab. It only takes foot traffic. So any suggestions as to how to fix this scenario? Only thing I can think of is fit a 600mm x 600mm cover and frame.
Any thoughts gratefully received.

 

[exedon2]

That looks like a standard polypipe 460mm inspection chamber
Lids readily available.

 

[Bogart]

Well all I can say it measures 480mm have just now double checked as I have been known to be useless with a tape measure.
No definitely measures 480mm. As does the rectangular lid that has rotted. I have found a 24in x 18 in which works out at
610mm x 457mm. Looks like this mine even has same sort of lifting fixtures.

 

[snowhead]

You say 480 diameter, that's probably 460 internal, see below,

In the COVERS section botom of the list

https://www.polypipe.com/housing/below-ground-drainage/drainage/inspection-chambers-covers-and-frames-polypropylene

 

[Bogart]

You say 480 diameter, that's probably 460 internal, see below,

In the COVERS section botom of the list

https://www.polypipe.com/housing/below-ground-drainage/drainage/inspection-chambers-covers-and-frames-polypropylene

 

[Bogart]

Is hard to determine but on the polypipe 460mm, that is the lid diameter as it states the frame diameter is 549mm

 

[Bogart]

Have bought a 600 x 600 Clark Drain galvanised cover and frame. With a bit of fettling of the surrounding ground should be ideal.

 

[Lou]

How did you get on fitting the cover?

 

[Bogart]

Was sure I had posted a photo with cover,frame fitted and then with patio slab on top. No idea where that went to. All went fine, made a change.