Easiest way of removing a 40mm pipe through a wall

[just pumps]

Ok, big assumption but If the external diameter of the existing pipe is 40mm, then you can get 1.5" (38mm) solvent weld couplers from here

Right I'll shut up now other suggestions are probably better.

Easy to buy straight connectors however not all plastics are the same hence there are different solvent weld cements out there.

 

[just pumps]

Chances are the foam is only just inside the hole by say an inch, so a sharp kitchen type knife might work here.

On reflection a sawtoothed plasterboard saw will be ideal (Short pointed blade like a knife).

 

[foxhole]

Cut each end, rotate to break foam seal and replace the lot.

 

[Madrab]

47mm hole saw on a battery gun on slow screwdriver setting, that will allow you to ream the old fitting off and a new one should then fit on.

 

[durhamplumber]

Depending on how tight the hole in the wall is to the pipe, i've used a long drill bit to mill the foam from around the pipe in the past. PU foam seems to stick quite well to plastic waste pipe.

Drill the lot out with a core drill

 

[andymartin86]

Thanks for all your help guys.
Managed to do it all in 2 hours. I broke the old elbow off and hit the end with a lump hammer. Slowly but surely it pushed back into the house. New one went in a breeze.

 

[Ian H]

Gutted, was just going to suggest dynamite.