Don't, whatever else you do, be economic with the truth. You are, to some extent, at their mercy. They are likely to see a record of your doing your best (which I infer from what you said) and if you give an honest explanation of your difficulties, then they will probably try to work out some arrangement with you. Banks don't want to drag people into courts, and they don't want to take your house; they want you to succeed in paying your mortgage.
Treat it as an opportunity to work out an approach that you can work with.
And MABS, did I mention MABS? Talk to them.
[Edit: Senna types faster than I do. Similar message!]