35Cl NQR and calorimetric measurements in BCPS have been reinvestigated between 77 K and room temperature (NQR) and between 100 K and 180 K (CP). It is shown that, in contradiction with conclusions found in literature, there is no lock-in transition at 115 K. These new results are in agreement with those obtained with other experimental techniques: Raman scattering, X-ray diffraction, neutron diffraction and proton NMR; the latter indicate that the incommensurate phase, appearing on cooling at 150 K, persists down to 4.2 K, at least. The shape of the 35Cl NQR spectrum in the BCPS incommensurate phase shows that the frequency of a chlorine nucleus is a function of the order parameter, through linear and quadratic terms.