Ozzym, my husband is in a similar situation at the moment aswell and I haven't been able to get any clear advice from SW or our Community Welfare Officer. He has a number of years service, the company are in trouble and the employer will not admit this. He has paid the staff cheques that have bounced last week and is going to do the same tomorrow. Husband doesn't want to walk out as he will lose his redundancy claim (which the employer is refusing to pay) and he will lose his JSB / JSA, not sure which.
I am trying to find the correct avenues where he can take constructive dismissal. Employer has lost the plot completely and thinks it is not his fault, his bank bounced the cheque. As far as he is concerned he paid the staff, as in gave them a cheque.
Hope it works out for you.