Thank you for your help, I have tried both versions of the function, but I am getting the same problem.

Now I either get exactly the same error, or sometimes it gives an error on the busy method instead of the navigate2 method

Method 'Busy' of object 'IWebBrowser 2' failed

It's the intermittant nature of this issue that is so frustrating.

Could this be something to do with the network settings I am using? I am doing this at work and the network is pretty locked down, might it be timing out and breaking the connection between Excel and IE so quickly?