Bathroom installation Connection of Shower and bath waste

Hi,
Please can anyone advise me on the connection of shower and bath to a common 43mm waste. I was going to run the waste from the shower tray in the 6" joist space to the outside wall, it runs out under the bath position so I was considering just tee'ing the bath into this run before the waste runs out through the wall to outside.

Is there a chance when emptying the water from the bath that it could back flow into the shower tray given the realatively shallow fall? (shower around 2M from bath) i have asked a couple of plumbers who both said it should be ok as long as there is a decent fall to the waste stack connection. Can anyone confirm this or is there potential to flood the bathroom via the tray.

Otherwise it means running 2 parralel wastes through the wall to the stack on the outside of the house which will look awful
Thanks.

The bath will drain very slowly so I would think you will be ok to tee into the same pipe.

If you do get a blockage however, it will flow back into your shower tray

Try it and see how you get on.

Do the job correctly and run separate wastes !!

A soil stack is not something people look at and say "That is really nice"

I feel that you are looking for a reason to cut corners and bodge the job!!

If it is your own home you should want to do it right!!