UK Landlord Forum / Life

So here is our situation - hold on to your hats!

We are in an AST until April 2013
During the last 6 months illness has changed our life and our ability to work
And we have no hope in being able to meet the remainder of our AST obligations
Thankfully we do own another property so we'll not be homeless but it also stops us getting housing benefit for current AST
We've been open and honest with the landlord but they are utterly dismissive and very aggressive towards us
We've provided them with a Deed of Tenancy Submission to release us, which they won't sign
We've offered to help find another tenant, and pay the tenant find fee but they won't instruct an agent
They've threatened to enter the property while we're still in - i've written to them warning them not too
The gas safety certificate for the property expired last July. I only realised last week and have told them, but no action from them so far.
My concern is they sit tight, and we rack up months of non-rent payment till April next year
I know they have a mortage on the property and need our rent to pay it

My questions are:

How on earth do we get evicted asap?
And when they evict us, are we liable for rent between eviction date and end of tenancy date?

Would welcome any thoughts!