Company ceased trading

I was informed on Friday for the first time that the small limited company I have worked for over 7 years was ceasing trading this weekend and that Friday was my last working day. The managing director is resigning and starting a new company on Monday and I have been invited (with my other few colleagues) to arrive on Monday and be given our P45's and then be offered similar jobs with the new company which will have different and less beneficial terms and conditions. I am the only one who has worked longer than 2 years and have not been offered any redundancy pay, notice pay or any information.
I have been looking on the internet and believe that I have to put in a request for these in writing to the old company and on the basis they have no money, that I will in time have to claim from the government. What are the implications if I do or don't accept the new job?
It appears that the company is not going into liquidation as yet, but I understand it may be forced to in time.
Is there a difference to my rights because it is ceasing trading and a previous director is setting up the new company and basically trading with the same clients and customers?
Hope someone is out there to give me some guidance today as I am unsure how to deal with the situation tomorrow. Thanks.

Turned up for meeting and eventually director arrives to say we should all work 'as normal' this week, because although the company had ceased trading midnight on sunday, it was going through a 'transition' week, whereby whilst not conducting new business, it would be discharging its responsibilities to its employees etc?
Effectively it would be a 'notice' week and we would not get our p45s until the end of the week. We got our new job offers with reduced terms and conditions, but the jobs don't start until next Monday. However the new company is trading now and the work we are doing is for both companies, depending on whether the task is related to the period before or from the 16th. I am confused, can he do this? And by now offering the job during a supposed notice period, have I lost the right to redundancy pay or pay in lieu of correct period of notice?
Any guidance would help. Thanks.