Will missing his bath really upset the routine do you think? I mean what if you were to go out anyway, feed him at his usual time and then just cuddle him for a while or settle him in his pram instead of bathing him? Then you could feed him at the usual time again and put him down for the night. With my babies, the bath time was never set because things would happen to change it, especially once we had our third and we had to fit her routine around the older kids. I would just work it around when they slept and fed and whatever else was happening that day. Some days there would be no bath - it is not essential, especially in the early weeks. And as the others have said - routines change anyway. Try not to over-think it IYKWIM, and don't let the routine dictate your life - a little flexibility will not hurt.