Jayne
Were you able speak to a Customer Services manager?
I am not surprised that you have not received a Statement of Reasons, of all those who have requested this, I know of only one that has actually received it.
I am afraid that a prognosis, of whatever length is not reason to appeal for the Support Group. See
Qualifying for the Support Group
Curtailment means that the ATOS assessor had already recommended sufficient points to qualify for the WRAG so they did not need to consider the Exceptional Circumstances.
This does not mean that you cannot base an appeal in part, or in whole, on the Exceptional Circumstances, but you should be aware that the burden of proof lies wholely with the claimant and you will need to provide significant and current evidence to support your position. Also, to qualify for the Support Group you need to show that carrying out Work Related Activity would pose a potential danger to your health, not just just working.
Gordon