boilermate 2000 - repairs in East Yorkshire

Hi. My 12 year boilermate ball valve in the expansion tank is seized and the water level is below any of the inlet and outlet pipe. I also have an issue with loud banging when heating is called for.
lastly the heating always comes on when the water is called for.

Has anyone had any experience of these potentially related issues and are there any repair specialists in the area?

Thanks

Andy

As for a repairer.

Google up Gledhill repairs or Boilermate 2000 repairs for your area.

Mike