Hi Gavin,
Did you try to install update 11 manually?
Like if you were able to download the .jar from CF admin then the hotfix_011.jar will be present in : C:\ColdFusion10\cfusion\hf-updates
Just copy and paste this .jar in C:\ColdFusion10\jre\bin and then run command prompt as Run as admin, change the directory to cd C:\ColdFusion10\jre\bin
java -jar hotfix_011.jar >>hotfix11.log
Observe that are you able to install the hotfix manually or not. If you face any issue, then share the info mentioned in the hotfix.log present in C:\ColdFusion10\jre\bin
Thanks
VJ 