How to stop VR character walking through walls?

I started a mine in 3rd person which was going ok. Having done a quick test with a VR set I decided to rebuild it in VR. Having set up the character, I decided to see if I could import what I had built in 3rd person to the new VR level. All the assets have copied over without to much of a hassle with exception of one problem. When I switch to VR to test it out, my character now walks through all the walls. Is there a way to deal with the problem as a whole rather than individual assets? If not I may as well just restart from scratch.