I tried growing a couple of tender plants one year. They did well during the summer but I wasn't sure about fleecing over winter, whether once covered, you left them all winter till the following spring or took the fleece off on warmer days. I also wasn't sure whether to dig them up and put in the GH.
In the end I tied both up, covered them in fleece and dug one up, to spend the winter in the GH. One was uncovered early spring but both died, they rotted in the centre, it was a particularly cold winter in 2010 but I haven't tried growing anything tender since then.