I'm not totally following you and remember you from before but not all the details.
Let's look at this another way. You can agree to pay the 130€ per month and not follow thru on it. But sign that you will so that you can get rid of this property. Otherwise AIB might scupper the sale.
Doesn't really matter what you sign as you owe them the money anyway (do you mind telling us how much AIB are losing on the sale - just want to get an idea of how much they will write down)
After the sale you will owe 10K plus 20K in CC. To AIB.
What can they do. They can go for an instalment order, but if you're at the limits (of the living limits of the Insolvency service) then they won't get an instalment order, they certainly will not get it if you are on social welfare.
So can they 'attach' the amount owing to a property. You have 3 mortgages with BOS, one of which is your home? Are all in NE ?
Have you considered going bankrupt. It's very cheap now and you can do it yourself. In addition you just need to pay a PIP around 250 (based on a poster I read yesterday) for a document stating you're not eligible for any other type of insolvency arrangement. Looks to me like the Insolvency service is now dying for customers as they're another white elephant and need to justify themselves, seeing as they've changed their tune they will be delighted to help you.