Henlow produced quite a report on the subject and CAM are quite good at providing reports when asked. If you are looking for a regular claim or similar then you may not need additional detailed evidence. If you have to bob your head around in a dynamic or vibration prone platform with a heavy Mk4 helmet + NVGs + counterweight + an odd CofG then it would be rather hard for the MoD to claim that this does not have a deleterious effect.