Hi Michael

We added the timestamp as you suggested and it has made no difference. We haven't done anything with the headers yet as we need to research how to do it.

I have tried adding the cache disable line to wp-config in live, but it didn't make a difference. I've also removed it from the wp-config in test and that also didn't make a difference. The only thing I can see which is different between test and live is that the test site is in a sub folder of live, but I have no idea why that would cause it to work in test. Is there anything else that staging does and I may be missing?

Thanks for your help.

Ian

Did you add a changing part in the return url?

Best regards, Michael

Yes we added a timestamp as you suggested.

Ian

Then I do not really understand how this can be cached. Do you have an url?

Best regards, Michael 

If you go here you will see a red button. That is the one with the returnurl on it.