Yes - through Tenancy Deposit Scheme.
Neither - we did not realise there was a 3 month time limit. We were waiting to hear back from landlord. They have now sent us a release form.
We are more concerned about having to pay rental compensation.
My main query was whether they can claim rental compensation from us for the time between our leaving and a new tenant taking over, even though they seem to have made little effort to do anything with the house for four months?