Right. If your employer has not issued you with a formal notice of redundancy (which is doesn't sound like they have, as they have set they'll "let you know"), then you appear to be on what is called "Gardening Leave". Your employer is required to give you a minimum notice period before termination of employment.
This has to be done in writing and must be legally correct. If they have not given you formal notice of redundancy, then they must give you the minimum period of notice before they can terminate your employment (unless you're being fired).
Look up the terms of your contract. It will state in there, the minimum notice they must give you in writing before you can have your employment terminated.
As for the whole time worked thing, your time worked does not cease until your contract has been terminated by the company.
I have a question though, are they paying you during these four weeks?