Nerium oleander is not really that hardy. How long have you had the plants? A winter like the one we have just had and you can probably chuck them in the skip!

Don't burn them though as the smoke is toxic - like all of the plant.

Thank you for getting back to me.The plants have only been in sinc approx April, should I just give it up as a bad job !! also are the plants toxic to wildlife??

These plants have a borderline chance of survival in the UK. I think they're beautiful too, but seem to be toxic to everything if enough is eaten. The toxic smoke is what put me off trying to grow them, you can't just burn any prunings.
http://en.wikipedia.org/wiki/Nerium_oleander
But it is resistant to deer!

thanks to everyone who replied