Minecraft Factions Base Defense?

I'm currently playing on mc.mineagepvp.org and we have a pretty powerful faction. For some reason, people have been able to glitch into our base. Please help us build up our anti-glitch protections?

Right now we have a sand wall going from bedrock to skylimit with 3 layers of half-slabs at the bottom to prevent hybrids. Inside of this sand wall, we have a pretty small base, going from y:30 - y:60, which is just covered in a simple layer of water with half-slabs at the bottom once again. This inner base also has buffer layers at the top and bottom of the base, both two layers thick and completely empty. Therefore, I think the glitchers have been somehow entering through the side of the base, but that would mean going through a water-sand-water-clay wall. How should I improve the anti-glitch defense on my base? Any suggestions much appreciated.

That base should be made out of obsidian, completely surrounded by water. Put extra layers of cobblestone all around the water, so it is too thick to enderpearl glitch through. Keep the rest of your fortifications.

I would suggest trying to put the block that takes the longest to brake, and put some sort of liquid barrier around your base