Stuck in a rut with nram, help needed please!

Josie03

Long story but here goes,

Bought house in 2005 and had a together mortgage, between then and 2009 extra loans were taken out to central heat/ replaster etc, now outstanding are 4 parts,

98500 sec
3300 sec
2700 unsecured
8000 sec

Estimated figures, there's is a total of 111500 outstanding, with 109,500 between secured debt.
Ex husband left in 2009 when I had 2 small children, the house is a two bed. I have continued to make every payment without him contributing so I am now remarried with 2 more children so there is now 6 of us in a 2 bed. Myself and husband applied to take the mortgage on in our names and pay for ex to be removed (with his consent) but nram declined so as we need to move we applied for consent to let one year ago, it was accepted for a year but we didn't move as we couldn't afford to run two houses if tenants didn't pay etc so I asked nram in June about my options for selling. Customer services advised that I could leave the unsecured debt behind and if I could provide a letter from a loan company saying I couldn't get a loan for the shortfall then they would look at a payment, is all I had to do was ring up with the offer I had received.
Phoned nram two weeks ago as we have an offer of 98,500, current value is around 100,000 and nram said I needed my income to be assessed for a payment plan for the shortfall so put me through to debt management who have declined for me to sell as they have said that I do not need to sell as I am not in financial hardship.
I have put in a complaint to nram but I have got an 8 week wait and have an offer!
Can someone please advice me on what to do?
Thank you