Some advise on soil stack connection on a 100+yr house

[HarryD]

Hello all,

First off I am a plumber by trade but I work almost exclusively on new builds so after buying my first house which is a little over 100yrs old this is a bit new to me.
I'm wanting to get a bathroom in upstairs in order to do so I need a stack up the side of the property, there is this which I belive to be a back inlet gulley (not 100% if not please tell me what it is 😁) am I right in thinking I can't just drop a stack into this and I would have to gun up the concrete and put in a new connection?

Any and all advise welcome

Thanks

Harry

I'm trying to upload a pic but it's telling me the uploaded file was not and image as expected...

 

[rpm]

Ongoing problem with photos/ links at the moment, admin are working on it so we are told.