  Elastic and semileptonic transition form factors for the kaon and pion are
calculated using the leading-order in a global-symmetry-preserving truncation
of the Dyson-Schwinger equations and a momentum-independent form for the
associated kernels in the gap and Bethe-Salpeter equations. The computed form
factors are compared both with those obtained using the same truncation but an
interaction that preserves the one-loop renormalisation-group behaviour of QCD
and with data. The comparisons show that: in connection with observables
revealed by probes with |Q^2|<~ M^2, where M~0.4GeV is an infrared value of the
dressed-quark mass, results obtained using a symmetry-preserving regularisation
of the contact-interaction are not realistically distinguishable from those
produced by more sophisticated kernels; and available data on kaon form factors
do not extend into the domain whereupon one could distinguish between the
interactions. The situation is different if one includes the domain Q^2>M^2.
Thereupon, a fully consistent treatment of the contact interaction produces
form factors that are typically harder than those obtained with QCD
renormalisation-group-improved kernels. Amongst other things also described are
a Ward identity for the inhomogeneous scalar vertex, similarity between the
charge distribution of a dressed-u-quark in the K^+ and that of the
dressed-u-quark in the pi^+, and reflections upon the point whereat one might
begin to see perturbative behaviour in the pion form factor. Interpolations of
the form factors are provided, which should assist in working to chart the
interaction between light-quarks by explicating the impact on hadron properties
of differing assumptions about the behaviour of the Bethe-Salpeter kernel.
