If the pipe ends at the burn it will be a soak away, this can be allowed through a licence, this would be with the EA in England or SEPA in scotland. With it being a soak away a dye test will probably not work. The pipe type you mentioned in the original post is also the norm for a soak away.
Is the end of the pipe flowing freely?
If you could send me some pics and a drawing i will have a look at it for you.