I'm surprised they even performed the procedure on you without using ABx.

I lied to them.  I told them I took the ABx.  I don't like lying to doctors, but sometimes you have to to get what you want. 

They seem insistent on it. Did you go back to them after when the procedure didn't work to see what they would say about it not working?

Yes.  They prescribed more ABx, which I did take this time, and what really stuffed up my candidiasis.

Why is there even a need for ABx if the colonic lavage removes 90+% of the bowel flora. Was this not something you had to do the first time.

Yes, did the lavage the first time.  Obviously they want to kill as many bacteria as possible, that's why you take the ABx.  The lavage will not eradicate species of bacteria, just reduces their numbers.  ABx eradicate whole species.

I had some klebsiella (dysbiotic flora) which they strongly suggest I eliminate before performing HPI.

They like to kill everything and try to implant afresh.

I kind of don't get it. Do they not perform similar stool analysis' to the ones we do in North america. Do they not detect the yeast in the stool?

No.  They don't do a proper CDSA, just look for certain bacterial pathogens, particularly C. dificile.  They're not interested in yeast.  I went back to them after the ABx, with an awesome white tongue and itchy bum from Candida overgrowth, and they weren't interested.  Just told me to take more ABx.  Didn't even suggest an antifungal.  They are in denial about yeast.  Politics of the medical fraternity!