An unhappy update on my situation.
Initially I sent in a letter with proof of income etc and Erudio refused to even process the deferment.
So then I had no alternative but to fill in the forms and black out the bits a didn't agree or consent to... I did this with much reluctance after assurances from one of Erudio's agents that she would send me letters confirming that my information would not be shared with CRAs and that I didn't need to provide Erudio with Direct Debit details... so I caved in and filled out the form and sent it off and found out yesterday I had been deferred successfully.
And then this morning I received a letter saying that...
"I can confirm that if you default on your student loan this will affect your credit file."
"Altho we will share information with credit reference agencies in relation to your deferment this is not logged as a default or in a negative way. Simply to help lenders understand how much credit a potential borrower already has."
...which is the exact bleeping opposite of what I was guaranteed!
I then telephoned and asked to speak to the agent in question... she apologised and said that she had believed at the time she was giving me accurate information but she could confirm now that I wasn't going to get the aforementioned letters of assurance and that my information WOULD be passed to CRAs regardless of me having blacked out bits of the form and written "do not consent" all over the damn thing. She also said that it was done now and couldn't be undone.
In essence she lied right to my face about everything just to get me to sign.
And to all those saying that filling out the forms but blacking out various bits is the way to get a successful deferment without agreeing to Erudio's changes to the original terms and conditions... this confirms what I have suspected all along which is that this is bullshit. Erudio will disregard your scribbling and share your information anyway.
I have logged an official complaint which the agent claims will be dealt with within five days... but seeing as my last complaint was rejected by Erudio without them even bothering to contact me i'm not optimistic.