Free GPS hiking app?

Off topic a bit, but have you had success downloading (uploading) the 1:50,000 topographical maps from the Mowbray Mapping ordnance centre to Locus maps? or any other mapping software that could then interact?

I last did this last century with Fugawi software and raster maps, I know things have moved along enormously since then, just curious as it would be fantastic to get them on my Garmin