Hi Maggie,
ATOS are always reluctant to carry out home assessments and it is entirely up to them whether to do so. However, they can sometimes be persuaded by strong supporting evidence from the claimant's doctor (GP or psychiatrist). If you can get such a letter and sent it to ATOS, along with a request for a home visit, you might be 'lucky'.
Nothing on this board constitutes legal advice - always consult a professional about specific problems