I don't think SC would ever have agreed to move back to Essex. If she did JB might have welcomed it. He may have said let's swap with SC having his cottage in Goldhanger and JB having SC's flat in London. JB could have worked on the farm during the week sleeping at WHF Mon - Thu eve and then spent his w.e's and holidays in London.
Sheila doesn't have much say. It's Neville's and June's money.
If Bamber was right and Sheila and the twins were moving into his cottage, that would infuriate Bamber. He had spent hours and thousands refurbishing it.
Surely Bamber wasn't going to move back into WHF. If not Neville would be giving him somewhere smaller to live in. Anywhere bigger available would have been given to Sheila out of neccessity.
Another option would be for Neville to increase Bamber's wages and tell him to find his own property. Which would upset him as it if he couldn't afford to buy or rent somewhere decent, he would have to live in a bedsit or shared house. Either which way, it was not benefitting Bamber.