We slayed the dragon, all was going great. We then teleported through the generated portal to explore the End and look for an Elytra. We found two cut off cities in three or four hours exploring. I then tryied using a website to find the End Cities because it was getting ridiculous. This is what I used: http://chunkbase.com/apps/endcity-finder#-8003071994535318968
And this is the seed from our server: -8003071994535318968

After we finally found a protal back to the main island (we were at -4500, -3000 and we had only seen one other portal back.) We finally were back in the overworld with just a tiny bit of loot from the cut of cities. I later checked in single player if the End Cities would actually generate properly there. It did. This was the result. The one from the third person perspective is the one on the survival server. The one in first person is from my single player.