Soil pipe side boss connector

[Tipper]

Hi all, I’m struggling to find the right connector to connect a new 1 1/2” sink drain to an existing blank boss on an adjacent 4”/110mm soil pipe.
I can’t use a strap on boss because of adjacent bends and connectors not leaving any space.
The boss is 50mm internal diameter but I can’t find anything to fit into it or something larger to fit over it.
The house is about 1990 build and I assume it’s metric.
What am I supposed to use…can anyone help?
Thanks

 

[RandomGrinch]

Unless I'm getting the wrong end of the stick:
https://www.toolstation.com/boss-rubber-adaptor/p37469
This goes into the boss, and the pipe slips into the hole!
Hope that helps!

 

[denso13]

The boss is 50mm internal diameter but I can’t find anything to fit into it or something larger to fit over it.

Any photos? Someone might perhaps recognise the manufacturer and know which boss adapter will fit.

 

[CBW]

You’ll likely need a boss adapter, but you can get varied one size for solvent weld and push fit, but as per @denso13 a photo would help immensely.