We'd love to see the final wetroom. :>
personally I have been fitting Impey trays for years, mainly for vinyl floors for councils but I have also done some tiled wetrooms with the Impey tanking kits and trays and I can highly recommend them. Doing a tiled wetroom at the moment using this kit, I will put some pics up soon
Most Wetroom/shower tray failures happen where the grout cracks, usually corners, so I always make sure that tanking covers the complete shower area including up the walls.
That's still not right your corner joint should be clear of grout and adhesive then it should be siliconed to allow for movementthe tanking kit comes with a semi curing Silicon which I apply to all the joins before any tiling is done, horrible stuff. I do grout my corners, then clear Silicon over once dry
Reply to the thread, titled "Liquid membrane over formed tray" which is posted in Tanking and Wetrooms on Tilers Forums.