Hi kah
Have you thought about consolidating your existing mortgage and secured loan into one? This may provide you with lower payments and you could then use the difference to support your son, but you need to be careful and you must not leave yourself exposed to an unaffordable mortgage into retirement.
I doubt whether you will be able to persuade creditors that a full and final settlement is viable, as a loan at 85% to the value of your property would only release £17k and your motnhly payments are quite high - also I assume that creditors have asked for a final year equity release.
Such a pity these education costs were not thought about at the time that you entered into the IVA.
Regards, Melanie Giles, Insolvency Practitioner for over 20 years.
To have me propose an IVA for you, please visit:
http://www.melaniegiles.com/ivaEnquiry.asp
See customer feedback at:
http://www.iva.com/iva_companies/IVA_Advice_Bureau.asp