Hi Andrew,

> (define-module (mytest f)
>   #:use-module (oop goops)
>   #:use-module (srfi srfi-1)
>   #:duplicates (merge-generics))

You need at least 

  #:duplicates (merge-generics
                replace)

but as I recommended in an earlier message, you should extend the default set

  #:duplicates (merge-generics
		replace
		warn-override-core
		warn
		last)

> ,in (mytest f) map

> While executing meta-command:
> ERROR: Unbound variable: map

The above will fix your problem.

David