DG
While the DWP require claimants to report an improvement in their conditions they are less fussed if they don't report a deterioration.
So the first thing for you to consider, is does this new diagnosis mean that you reasonably meet the criteria for a higher Mobility award?
If it does then consider notifying the DWP but be aware it will mean a new form and almost certainly a face to face assessment and the Decision, whatever it is will replace your existing award.
Gordon
Nothing on this board constitutes legal advice - always consult a professional about specific problems 
