This is a simple site but so packed full of information. The crew stories are particularly worth reading: Welcome to the website of the Force Z Survivors Association
And this is an interesting article on the analysis carried out by divers on the hulks of the Repulse and the Prince of Wales: http://www.explorers.org/expeditions/reports/Expedition Job_74_web_version.pdf
On the Force Z website, see the section on SS Automedon. Sending information by insecure means is apparently not a new habit of the British Government and Armed Forces!