  We calculate the differential cross sections for proton elastic scattering on
the exotic halo nuclei $^6$He and $^8$He at energies around $\sim$0.7 GeV at
the momentum transfers squared up to 0.30 (GeV/$c$)$^2$ and investigate the
influence of the nucleon centre-of-mass correlations on the calculated cross
sections. In particular, we show that the approximate account of the
centre-of-mass correlations used previously considerably overestimates the
cross sections at high values of the momentum transfer.
