ajmutally
The law is unclear in this area. I'm not aware of any specific requirement to notify the DWP but it may be to your disadvantage if you do not notify the DWP, for example a new ESA50 can be issued and require to be returned within the 28 days, if you are in the WRAG then your could receive notification of a mandatory activity which could lead to a sanction.
You can go away multiple time, it is not a maximum of 28 days in one year, it is a maximum of 28 days at any one time.
Gordon
Nothing on this board constitutes legal advice - always consult a professional about specific problems 
