The Returning Officer for each constituency will be designated by Welsh Ministers.1
Insurance
You are personally liable for the conduct of the election, you should ensure that you have appropriate insurance cover and should be prepared to demonstrate robust planning and decision-making processes in the event of any challenge to the election and a claim against this cover.
The team at your council dealing with insurance may be able to help determine what existing cover is in place and available, and to provide advice as to whether it should be extended.