Thermoelectric transport phenomena in a single-level quantum dot coupled to ferromagnetic leads are considered theoretically in the Kondo regime. The dot is described by the Anderson model with Rashba type spin-orbit interactions. The finite-U mean field slave boson technique is used to describe transport characteristics, such as the heat conductance, thermopower and thermoelectric efficiency (figure of merit). The role of quantum interference effects in the thermoelectric parameters is also analyzed.