AA
There are two issues here.
First, any work that you do, at home or away, must be declared to the DWP.
You can do Permitted Work with ESA, there is a guide in the ESA section but there are limits on the hours that you can work, less than 16 and your earnings of less than £167.00 each week, after tax and National Insurance has been taken off.
PW does not exist in UC your earnings will be treated in the same way as any other person's would. The only limitation is that you cannot work for 16 or more hours a week during the assessment phase, if you do then you will no longer be treated as having Limited Capability and will be moved into the All Work Group.
In terms of an award, the WCA does not take into account whether you work or not, only whether you score enough points for LCW or you meet one of the LCWRA Descriptors, so providing there has been no improvement it won't be an issue.
Gordon
Nothing on this board constitutes legal advice - always consult a professional about specific problems 
