I think this one uses electricity, so to some of us does not count as a hand tool!
But the blades you want are a standard fitting for all similar power planers, 82 mm long. Should be easy to find retail, or you could get them from Axminster by mail order here:
Hmmm, you may be right about the electricity, but it would be very difficult trying to use this with your foot!! Are you certain any 82mm blade will do the job, because none of my searches bring up the PHO1, most enfuriating. Thanks, Paul.