Perhaps someone can advise me where I am going wrong.

I have no trouble getting roman numeral page numbers in the footer text 
in frontmatter with

\startsectionblockenvironment [frontpart]

\setupuserpagenumber [numberconversion=romannumerals]

   \setcounter [userpage] [5]

\stopsectionblockenvironment

\startsectionblockenvironment [bodypart]

   \setcounter [userpage] [1]

\stopsectionblockenvironment

\setuppagenumbering

   [alternative=doublesided,location={footer,middle}]

But if I change to \setuppagenumbering[location= ], and choose, for example:

\setupheadertexts

        [ ]    [{\getmarking[chapter]\hskip1em \pagenumber}]

        [{\pagenumber \hskip1em \documentvariable{metadata:title}}]    [ ]

I get my header texts with page numbers in arabic numerals in 
frontmatter. I have tried various \setupheadertexts options, but I still 
get arabic numerals in frontmatter. The conversion does not work.

What am I missing or doing wrong?

Julian