That sounds like a good candidate for an A/B test on a different domain with the same database. I can create a virtual domain for install fairly easily. Happy to assist if this is helpful.
I've created a new virtual site ready for testing. If anyone at Una wants to let me know an install process for the test code - I'll get it up and running. Alternatively, AlexT has a login to that server - can SCP it up... but we'd need to discuss to confirm location for upload.
