Hi Andrew,
I wrote you a long reply on Sunday, but it disappeared into the electronic mists. So here it comes again.
The World Book of House Plants (ISBN0-308-10087-5) has the following to say about caring for oleanders (Nerium oleander). "Oleanders are easily kept to an appropriate size for indoors by pruning, either after flowering or in autumn. English references advise the prompt removal of any shoots which issue from the base of the flowers. The juice in the stems is poisonous, however, and clippings need to be discarded carefully, where children or pets cannot get to them. CULTURE: Light, sunny to semi-sunny. Temperature, cool in winter, average house at other times . Humidity, 30% or more. Soil, equal parts loam, sand, and peat moss; keep evenly moist, except on the dry side in late fall and early winter. Feed biweekly in spring and summer. Propagate by rooting cuttings of firm tip growth in spring or summer."
Now for my own experience... I've had a pink-flowering oleander for a couple of years. It lives happily in the garden (semi-shade) in summer and joins me in the house for the winter (in front of a sunny window). The only problem I've encountered is scale. The dastardly things love oleanders and you have to keep a close eye on them. They're fairly easy to control with a mixture of water, crushed garlic and dish detergent, but I have to repeat the treatment often. I can't seem to really get rid of them.
Oleanders are pretty tough and can withstand really brutal treatment. I traveled in Corsica this past spring. The people I was staying with have an oleander hedge. Whenever it gets too tall, they prune it way back, almost to the ground... with a chainsaw. The hedge doesn't seem to mind at all. If you decide to use a chainsaw to prune yours, I suggest doing it outside. Kind of stinks up the house if you use it inside.