the time taken to upload halved. It is puzzling because as you say it's not that much to upload.

Maybe it was the load on the server? meaning dealing with multiple requests at the same time delayed the requests?!

For now I've whittled down the number of entries to a more select but useful few and that has solved the issue. If it crops up again I will try

connect_configuration

properly.
Thanks for your help!

My pleasure 🙂