  The relativistic problem of motion of a classical electrical point charge
that has been placed between the plates of a charged capacitor and then
released from rest is well-posed in Bopp-Land\'e-Thomas-Podolsky (BLTP)
electrodynamics. That theory introduces a single new parameter, Bopp's
$\varkappa$, a reciprocal length. The present article concerns the
small-$\varkappa$ regime. Radiation-reaction effects on the motion are shown to
appear at order $\varkappa^3$. It is found that in the initial phase the motion
is accurately accounted for by test particle theory, with the inertia
determined by the bare mass of the particle. Subsequently, radiation-reaction
effects cause substantial deviations from the test particle motion.
