To me there are nuts where you are being unreasonable, and bits where you're are not.
He should not be pressurising you into having another child, pretty alone at 6m pp. That is ridiculous. Equally though, where a woman had a desire for more children and her partner refuses, there is often support for her leaving if it's that important to her, do if he is desperate for a large family and that isn't an option, then I could see how it could eventually be a proven, and that's not one's fault really. But at 6m pp very few women are ready for a second child, and it sounds like your body needs time to heal. He is being utterly ridiculous about this.
However, I don't think he is obliged to support you bring a SAHM, just because you can survive on his eye, and the fact that it would mean a ridiculous commute back to your family is because of your very unusual attitude towards childcare, which isn't really feasible if you live away from family.
If he's only a year ago bought a home in Kent and he is the main bread earner, I don't think it's fair for you to demand he move to Dorset/Hampshire. The house was bought when your were pregnant by the sounds of it, and you knew your were moving there, so I don't think it's unreasonable for you to give a proper go at living in Kent.
It sounds to me like you didn't talk much about your plans for the future, how children would be raised or your prospective roles before having children.
He seems set on having a 'wife' rather than you, and you seem unwilling to try compromise on work or childcare or location.