The MS5.0 model is a narrow plate version of the GHD 5.0. For more technical information on the GHD 5.0 Gold Series models see our 5.0 page (on UK site).
We have a repair guide (on UK site) that covers this model here (it is the same inside as the mk4 models). If you don't fancy doing a repair yourself, this model is covered by our fixed price repair service.
If you are unsure which model you have, please see our GHD models page (on UK site) which shows you pictures of all the different models.