Shower leak

Ok, got pics this time,
The grout is actually not leaking, although I emagine it may well be leaking now i've started scraping it out to try and get the drain out.
It seems to be leaking somewhere down the PVC connections.

Problem is from the bottom, the water comes from up high somewhere above the boards so we can't see exactly where it starts. And from the top right now we have very little to see.

Basically, am I doing the right thing, scraping away the grout, then trying to remove the 4 tiles directly around the drain to remove the drain and try see whats leaking?

Any tips on the tile removal? I'd like to not break the tiles if possible!

Thanks!

Oops, here's the pic of the drain from the top..

please keep all posts in the same thread. it makes it easier to help you and less confusing to those who have the same problem.