No light meters, i hadn't even thought about one!

Well, this could explain a few things... It's being moved around quite a bit to get the sun at certain times. It starts in the greenhouse and stays there if the weather is crap, if it's sunny then she has a day out. It's a bit of a pain lugging round a 7ft plant and i have to angle it through the greenhouse door, as the height is 7ft!. Do you think that could be the problem? Should it be kept in one place only?

Thanks!