Central Bank Rules, Trading Up & Negative Equity

Hi,
I have never posted on this site before but often consult it for advice.
My husband & I bought our first home 10 years ago & have been in negative equity for most of that time. We have a young family & need more space than our current home provides, but haven't been in a position to consider this until recently. We had our home valued in the last month and the valuation was more or less the same as the remaining balance on our mortgage.
We have a tracker mortgage with BOI & when I explored our options with them recently, I was given the impression that we would need a 20% deposit if we were trading up & selling our current home. We could probably just about manage this but it would leave us with no savings, which I'm reluctant to do. Looking at all the information here, I have two questions:
1. If we were to sell our home & still be in negative equity (even if only by a small margin), would we only need a 10% deposit?
2. If we were to break even on the sale of our home, would we then need a 20% deposit?

I have discussed the situtation here, and you need to make a submission to the Central Bank to show them how you are affected by it.
What about people stuck in apartments who can't trade up?

If you are in slight negative equity, you need only 10% deposit.

If you wait a few months and go into positive equity, you need 20%.

Brendan

Thanks for your reply. Is there a specific format to follow to make a submission to the Central Bank?