The BBC doesn't deem it necessary to give a link to the article, here it is:
External Link/Members OnlyThe paper doesn't actually offer any evidence that mouthwash works - just that some (MSM) men were willing to try it. As far as I know, there is no evidence that mouthwash helps to combat pharyngeal gonorrhoea anywhere in the literature. Some sexual health organisations explicitly advise against using mouthwash before/after oral sex.
Looks quite an obscure paper (obscure journal, very few references) -- no good reason for the BBC to report it. I think they just like to report scare stories involving gonorrhoea.