Replace soil stack

Hi, so you can replace the soil partially or fully. It can be done with an angle grinder or 4inch cutter in stages. It should have brackets holding it in place. So a piece of the bottom will be cut with the grinder. This is so we can block the pipe at the bottom to stop debris getting in there. After that cut the pipe after every bracket. Then smash it with a hammer it will shatter. The higher parts, use an angle grind and partially cut it. Tie a rope around these pieces and then tightly tie the other end to the direction you want it to fall. Then hammer the partially cut part, it will break and fall away from you, windows etc due to the rope pulling it away. You can use band seals to connect parts that join old cast with new pipe. All together it's heavy, but in pieces light and easy to manage

any good qualified plumber can undertake this job for you.

Contact a local builder and a plumber, a local plumber may even take on the whole job as you would need to connect your w.c up to the new pvc stack. Maybe worth re-routing your bath and sink into the new stack as I'm guessing your current set up has a separate bath and sink waste into a hopper or similar. *Dont go for the option where you use a 4'' rubber couple to connect pvc to old iron at ground level without excavation. it may be a cheaper quote but will give you blockage issues further on in years* Care should be taken when excavating the base of the old iron stack and removal from the clay knuckle into the sewer. Thames water etc will not be happy if you loose a chunk of iron in their pipes. Would suggest an access tower for removal and should be easily achievable for any skilled person and a labourer.

A painter should be up to the job of painting it . To replace you’ll need a plumber .