Well done, Dave. Easy, really, with no safety risks or ‘hic-ups’.
I had the benefit of a sturdy little sack barrow with which to move the base (and the column) of my grinder for most of the distance required.
The planks I used as an inclined plane were 2 off, 1.5m long, 200mm wide and 45mm thick. They were not likely to bend! With a fall of about 650mm, I had to pull the base down the slope. I removed the motor from the base before moving the base – but particularly because it was to be taken apart to convert it for 230V operation.
Other parts (head, table, cross slide, knee, motor and mag chuck) were carried with no great difficulty (table was heaviest).
It looks like your mill would only present a lifting problem (needing two people), with the base (perhaps) and the column if it were dismantled further, to its main components – but as it is I think it may need something better than one of the cheapest engine cranes on the market, as that lump certainly looks heavy!
If I don’t have a pump truck, or other easier alternative, I roll a pallet along on pipes, if on a good surface. Slopes and turning corners is ‘fun’ one can do without.