The geometries are pretty different – different enough to make a size coparison between 19″ Latitude and large Parkwood quite tricky I’d have thought. The Parkwood does have a longer ETT, but due to slacker seat angle the ‘reach’ is shorter by about an inch (so will feel shorter stood up). BB on the Parkwood is also a centimetre higher and head angle 1.5 degree slacker than the Genesis.
Obviously the Parkwood is going to be a very different bike to ride the Latitude. I suspect it will feel a bit bigger when sat down, but not loads bigger. Parkwood’s style and head angle would suit more of a shorter stem than the Genesis too, so you may find you loose the extra length you were looking for there.
Sorry – that’s not actually very constructive help is it? 😉