I have moved some full grown Lupine plants to another part of my garden. They don't seem to be standing up as they should. Should I perhaps take some height off them to give them a chance to recover?
Yes, cutting back the foliage on a transplanted plant is always a good idea, to make up for the roots that were lost. This article has some insights into lupine care that you may find useful: https://www.gardeningknowhow.com/ornamental/flowers/lupine/growing-lupines.htm