General ⇒ Fix harvard \citeasnoun to use 'and' rather than '&'

[outspokengolem]

I am using the agsm bibliography style. This style uses an ampersand in citations in place of the word 'and' before the last author in the author list. This is inappropriate for in-text citations using the \citeasnoun command because it is not correct to use an ampersand in running text. How do I fix things so that 'and' is used for \citeasnoun but '&' is used for \cite?