Get Gluten Sensitivity Test in the UK

Since I was a child I was eating normal diet and I know something was wrong as I wasn't gaining weight and always need to go to the toilet, but for the past year I have been trying a gluten free diet and it's working, I'm better in myself and gaining weight which I would never thought it would happen. It's going to take a while for my stomache to repair it's itself after years of abuse eating the wrong diet. My goal is to people who aren't coeliac and know there diet is better on Gluten Free diet is to get tested for Gluten Senstivity and not just Coelaic Diease as for me they have always come back negative but I know there is something wrong there.