Soil pipe adapter - Cast Iron upper to plastic lower

[Gooman]

I need to have a soil pipe relocated for the ground floor section of my new home. Our builder is fine with the below-ground works, but I want to check my options on above ground.

 

The soil pipe is cast iron, and goes through the soffits and then through the tiled roof. As the soffits are asbestos cement board they're best well left alone,so I want to leave the first-floor part of the cast iron pipe in place, then convert to plastic to run at an angle to the new vertical downpipe to connect with the new ground-level drain.

 

The only adaptors I can find are the SP140 but that's for a plastic upper to a cast iron lower. 

 

Any good sources or bright ideas?

[Mr Punter]

Maybe you could use one of the band seal connectors but I am not sure if they can be used on an external stack.  I have used them below ground.

[AdamSee]

This is the comapny you want to check out - https://www.flexseal.co.uk/products/flexible-couplings/ 

They do a coupling for every type of waste pipe. Takes a while to find what you need but you guarantee it on there. I usually find what I need the look at Wolsleys Plumb and Parts centres website as they usually stock these.