Do I need a new inspection chamber or rodding point?

[LakesDylan]

I'm digging under my foundation walls (350 year old chapel) to install a new 110mm foul water drain.  This is the only drain coming from the building.  It will then join into the adjacent properties pipework (with legal agreements in place) via an existing inspection chamber, less that 6 from the outside of the chapel wall.   It is a straight line from A (the chapel) to B (the inspection chamber).  I will put rockers/flexible joints either side of the wall, but was wondering if it was necessary to add an inspection chamber or rodding point?   I can easily gain access to the existing  inspection chamber and work back if here are any problems.

 

Any advice greatly appreciated.

 

[PeterW]

For the cost of an IC, depending on depth I would install one anyway as a demarcation chamber.