ATOS will scrutinise the ESA50 and decide whether they have enough information to make a recommendation, or whether they want to call you in for a face-to-face assessment. When ATOS have made their recommendation (after seeing you if they deem this neccessary), your file will be returned to DWP. This process can take anything from days to months (it was 5 months in my case but some areas manage to deal with things in a more timely fashion).
Nothing on this board constitutes legal advice - always consult a professional about specific problems
