  There has been substantial investigation in recent years of subdirect
products of limit groups and their finite presentability and homological
finiteness properties. To contrast the results obtained for limit groups,
Baumslag, Bridson, Holt and Miller investigated subdirect products (fibre
products) of finitely presented metabelian groups. They showed that, in
contrast to the case for limit groups, such subdirect products could have
diverse behaviour with respect to finite presentability.
  We show that, in a sense that can be made precise, `most' subdirect products
of a finite set of finitely presented metabelian groups are again finitely
presented. To be a little more precise, we assign to each subdirect product a
point of an algebraic variety and show that, in most cases, those points which
correspond to non-finitely presented subdirect products form a subvariety of
smaller dimension.
