Yes, I have and it's impossible to get close to the edges of the Dome port. I damaged my dome by trying to fit it without the extention ring after changing to a 12-24mm Lens. What happens is that the repair scratch area get larger each time you change the micro mesh. You have your hand half inside the dome and use your fingers to hold the mesh on the foam pad provided with the kit, whilst trying to keep even pressure on the pad. Unfortunately, the pad is flat and against the double inside curve of the port, only the edges of the mesh are in contact with the dome. I also tried to remove the dome from the port backing and failed - ended up buying a replacement port from Aquatica. Unless you can remove the dome from the backing plate your going to have a nightmare of a job. Also another point to consider is, if you only polish a small area you will change the optical properties of the dome and end up with localised distortion when looking through the port. This is a fact I have learnt from polishing aircraft canopies. Good luck.