ESA50A

Hello everyone.
I am not sure if anyone else has had this problem, so here goes!
IB to ESA conversion.
Finally received response from DWP to my SDA request, which confirms my concerns that repeated errors have been made by DWP.
Specific query:
I sent in an ESA50 and 7 pages of supporting docs received by DWP and date stamped 24th October 2011.
ESA50A completed by nurse on 2nd November 2011.
States
Advice:
"I am unable to advise on the evidence held. The case will need to be referred for assessment"
Justification of Advice
"A recent ESA50 was not available so the claimed level of disability is unclear. Scored on physical points at last exam"

Seems from this that the HCP did not have the ESA50 at the time of writing the report.
I sent a subsequent letter to the DWP on 21st November 2011 expressing surprise at being called for an assessment given the detailed info I had submitted with the ESA50. Not received a reply to this despite a further letter chasing up sent in Dec 2011.
Now wondering why I bothered with the ESA50 when it clearly has not been read!
I have been unable to attend the WCA due to being too unwell on the day.
I received a new appointment last week via the same post as the papers from the SDA request.

I am thinking that I need to ask for the ESA50A to be looked at again, as clearly the scrutiny process has not been properly followed through.
Should I write to the District Manager at the Benefits Centre, or to ATOS?
I sent a formal complaint into the DWP on 16th August to complain that a change of address letter I sent had not been properly actioned resulting in appointment letters being sent to my old address by ATOS. Funnily enough, I and have not received a response to that one yet......it would seem pointles sending yet another letter of complaint to the same office.

It sounds as if DWP/ATOS have acted with their usual (in)efficiency.