Envirowarm Services LTD (based in Hull) recommended and installed a quality Viessmann boiler in my house 10 years ago (saving me a lot of money over the British Gas quote for a lesser boiler) and have serviced it ever since and carried out replacement of what I consider to be serviceable items on it recently. We have found the quality of our Viessmann boiler to be excellent over the last 10 years and Envirowarm Services LTD to be totally reliable, with friendly, trustworthy staff that are highly qualified and experienced. Prices for boiler installation, servicing and repair have always been very reasonable.