Mine was fitted by VWR and it was pointed out that where the pipes go into the head you can put your fingers in and make them touch so I don't see what difference it would make which way round the pipes were?
....Mine was fitted by VWR too. On 22nd September by Simon.
I think it's only because of specific instructions in the BSH pdf and seemingly contrary info recently reported that is causing some of us to ask questions.
The only person who can definitively give us the correct information is Phil @ BSH or someone directly on his behalf.