If you haven't moved it don't. Most of the time pianos older than 50-60 years have structural damage rendering pianos PSOs (otherwise known as piano shaped objects). So get a piano tech to check it out first. If you already moved the instrument then in the US find a registered technician from www.ptg.org
Well Ian~Then I would say it's obvious you live in an area that doesn't experience drastic shifts in humidity. In the NE of the US - say Massachusetts - relative humidity levels in the middle of the winter go down to 19% and in the summer go up 100%. Small grands carry at least 36,000 lbs of string tension and quite frankly, in this region after 50 years you can hardly find an instrument whose pinblock is not loose, or that doesn't have cracks in the bridges or soundboards. Pianos here just can't handle those shifts in humidity - it rips them apart - it doesn't matter what brand or how "well" they were taken care of. However, I do remember pianos coming in for rebuilding that had lived almost their entire lives in the SW - like Arizona - those instruments were an entirely different story. No humidity shifts to speak of, no cracks in the bridges, soundboard, etc - nothing. It was eye-opening.