Solved it!

The issue of whether a toilet roll should be underslung or overslung. All you need to do is buy yourself a toilet roll holder like the one in the picture, install a second toilet and hey presto, you can choose the seat that presents the toilet roll to suit your own preference. Better still, you can chat with friends about the pros and cons of each presentation whilst conducting your business so to speak so I've not only invented a solution to a major problem but I've also invented a time saver. I can see this taking off in major corporations who are looking to increase staff productivity, after all, why stop at two? Arrange them in a circle and the potential is limitless, meetings on the go!