converting a back inlet gully into a new svp?

[GreatPretender]

Morning Chaps & Chapesses - long time listener, first time caller.

I have recently bought an old victorian semi and would like to install a new bathroom suite on the first floor. The existing wc is in a recent extension on the ground floor and has an s-trap pan, therefore there is no svp for me to connect into.

However, there is a conveniently placed back-inlet-gully into which the kitchen sink discharges and I have consulted a couple of plumbers with a view to converting this gully into the new svp. Now, I have only simple plumbing experience - part 'A' plugs into part 'B' and water flows.... - but I have been quoted in excess of £1000.00 for making this connection.

I would dearly love to gain more hands-on experience but the extent of the quote tells me that it is a reasonably specialist procedure. Is this indeed a job for professionals only?

 

[Bahco]

You will need to speak to your building control officer as any changes to existing drainage have to be approved. They will advise if the existing drain can be used or whether it will need to be modified underground as there is minimum bend radiuses etc.
Why not ask a local builder to do the underground bit and you fit the sv pipe yourself, it will be a lot cheaper.
Make sure the top of the pipe is 3 metres away from a window or if not 900 mm above

 

[GreatPretender]

BAHCO, looking in the existing manholes, the drainage is at least 3.5ft underground and the gully connects into it further down the run. How can a building control officer determine the appropriateness of the pipework without digging it all up....

...or have I just answered my own question?