Our sample of giant radio-source candidates , published in Paper I , is updated and supplemented with further radio and optical data .
In this paper we present : ( i ) newly detected host galaxies , their photometric magnitude , and redshift estimate for the sample sources not identified yet , ( ii ) optical spectra and spectroscopic redshift for the host galaxies fainter than about R \approx 18.5 mag taken with the Apache Point Observatory 3.5m telescope , and ( iii ) the VLA 4.9 GHz total-intensity and polarised-intensity radio maps of the sample members .
In a few cases they reveal extremely faint radio cores undetected before , which confirm the previously uncertain optical identifications .
The radio maps are analysed and the polarisation properties of the sample sources summarised .
A comparison of our updated sample with three samples published by other authors implies that all these four samples probe the same part of the population of extragalactic radio sources .
There is no significant difference between the distributions of intrinsic size and radio power among these samples .
The median redshift of 0.38 \pm 0.07 in our sample is the highest among the corresponding values in the four samples , indicating that the angular size and flux-density limits in our sample , lower than those for the other three samples , result in effective detections of more distant , giant-size galaxies compared to those detected in the other samples .
This sample and a comparison sample of ‘ normal ’ -size radio galaxies will be used in Paper III ( this volume ) to investigate of a number of trends and correlations in the entire data .