I like the neat and tidy way u made a access hole for heating rod and ppr plug in. And your integrity to show the botched first attempt and finding out the reason. This ppr plug in leak repair method has been proven to work. I see no reason why the repair will fail in future. Good job! By the way, I observed that the punctured pipe was embedded quite deep and this mishap should not had happened. Typical wall anchors are about 30mm, whenever I do installation, I drill just deep enough for wall anchors and use correct length screws to secure the items to wall.