Honda-SOHC

Dyna is about the best but not cheap.

I would caution against the Dynas. In recent years they have been faliling in large numbers. I have a Pamco and I like it very much. The Hondaman unit is also getting high praise.

Honda was selling "official" exhausts for a short time here in the U.S. The complaints were the same, dents and poor quality chrome. I would imagine Honda is also sourcing parts from Vietnam, China or even India. My friend has replica parts for British cars. He found an outfit in India. I work for a Japanese Company and they are not above buying parts in the 3rd World and some of them are junk. 

I have done tests and Simple Green is very impressive at removing fuel varnish. You can use it indoors with no concerns. I am not sure it is available in the UK.