I have found this Code of Ethical Business Conduct for Concentrix / Synnex Corporation. It has been extremely hard to clarify whose code of conduct Concentrix adhere to, it should be HMRC's.
files.shareholder.com/downloads/SNX/0x0x686839/7248E741-BB76-4813-A6B1-01F0C22D3391/Code_of_Ethical_Business_Conduct_English_.pdf
At the same time I sent the ridiculous pile of documents to them, on the 2nd June 2015, I sent a Subject Access Request. On the 17th July I actually had my original SAR letter sent back to me, with no response to it. This was beyond the 40 days they had to respond to it, as defined by the Information Commissioner.
I telephoned Concentrix (they block emails sent to the company by individuals) and asked why it had been sent back to me and not responded to, I was told that 'it was no longer needed'. That was not for them to decide!
I have now telephoned the Information Commissioners Office and been advised that my original request is still valid and that I should write to them again, this time, if they don't provide the required documents within 14 days, I can make a formal complaint to the Information Commissioner, who will then pursue the matter and investigate. I will be doing that.
Penny