Hmm, well it's a result of this winter, I'm afraid. You're lucky it escaped without damage in the previous winter, many people lost theirs a year ago, and this year's even worse. Not quite sure what you mean by Torquay palm - it's usually Torbay palm, and often they're actually Cordyline, but not necessarily. Check the trunk for signs of rotting or sogginess - if you find any, you will have to cut back past that point, to healthy growth. Then just wait - it may shoot from the base, or from further up the trunk, or the top may recover. You may not know before June whether it will grow again or not.