what's going on here?

[Robbox]

!960's house, this is WC soil fitting that goes into the concrete slab. It looks unusual, it's not a 102mm pipe into the slab. It's more like 90mm diameter. Why was this done? Surely back in 60's they used 4" clay pipes.
We want to update with back to wall or wall hung toilet, with a hidden cistern. But so far it looks like the door will open very close the the WC. Want to move WC closer to wall.
Once the builders take this out, what will they most likely find?
That mark is 220mm from the wall, is there a fitting that would allow the WC outlet closer to the wall?

 

[just pumps]

Under that pan connector will be a collar which the new pan connector will fit into and look at McAlpine Swan neck pan connectors.
https://mcalpineplumbing.com/wc-con...ing-bend-adjustable-length-rigid-wc-connector

 

[Robbox]

could it be made to work with framed cisterns, like Grohe etc? They all seem to come with a normal 90deg bend connection. Could that be replaced with the one you suggest?
I have found a wall hung pan that is compact at 480mm. It would be nice to limit the total overall projection to 700mm.
With that swan neck fitting, it would still require a reducer?

 

[just pumps]

First off you have to expose what you have just below the floor and there are different Swan necks available so I wasn`t saying that`s the one you need. Have a measure up to see what fits.

 

[Robbox]

Ok, thanks.