Hi Darren,
What happens if you open the Designer and simply log in to your web service, or is that possible?
If you can log in then open the report and it should allow you to refresh. If not can you enable DB logging?
Use this kbase to enble CRLogger - 1553469 - How to enable Database logging in Crystal Reports for Visual Studio 2010
Find crlogger.dll, it will be different location but should be there. To disable logging just rename the dll to *.org. Remember patches will instlal the dll so you have to rename it again. Or remove the environment variables.
Don