The new diagnoses will be irrelevant unless they have led to an increase in your mobility and daily living needs. Arguing that you have deteriorated is also a double edged sword as they can only look at you as you were on the date of claim so any deterioration would not be taken into account. Better to argue you were bad enough to qualify in the first place in the first instance. You need to do a mandatory reconsideration within 1 month of your decision and use the many tools available online to self assess and identify how many points you ought to score so you can identify what the DM did not pick up. Also, there is now caselaw about the need to for DWP to explain a different award. That will come in handy further down the line.