From my understanding if you have a CTTT ruling but the EC are splitting hairs you can then go to a Tribunal with this new information (more extensive damage than first realized) and get a further ruling from them to compel the EC to completely fix your bathroom.
When you go to the tribunal make sure you take a quote for the full cost so that if the tribunal finds in your favor they can tell the EC to authorize the repairs based on the quote immediately (make sure you invite the EC to obtain a second quote if they wish).
Also tell the EC what you are doing and that you willl also be asking the tribunal to impose a fine on the EC for failure to comply with the original ruling (up to $5,500). This threat might make them comply without the need to go through with it.