It is your choice to change to a new insurance company but a word of warning: you may find that your new insurer won’t cover any conditions which are covered by your current insurer.
This is because they are considered to be ‘pre-existing’ conditions which insurance companies have on their list of exclusions. So it helps to be healthy with no chronic conditions if you are looking to move to a new insurer.
If you are looking to change insurers then it’s a case of looking around until you find the right one for you. When you do find a suitable one, ask them about your current level of cover and how that will be affected by this move.