breach of tenancy agreement within two months of start of tenancy

Tenancy Types and Management

I let out the ground floor flat under an AST effective from 01-02-07
to two men in their mid-20's. They paid a month's rent (£325) &a bond (£325): on 01-03-07, they both failed to find the following month's rent. One of them had "lost" his job &could only raise £50; the other had failed to find any work (despite his initial optimism) &could only find £70. I have also received two complaints from neighbours re: loud, late-night music &other noises. I have advised them that they are in breach of the tenancy agreement.
Can I take any other action at present?