Notice extension declined by some, will leavers have a case if shift continues to run

My factory runs 24/6. Through natural wastage we reduced to 24/3 + 12/3 last year. Work has continued to reduce so we are now reducing shifts to 12/6 and this has resulted in compulsory redundancies. Consultation & notice period letters all given and accepted. Affected staff understand and whilst not happy can see why this has happened. With 1 week to go we have suddenly seen a big surge in both enquiries and orders. Out of 3 staff working nights 1 is due to move to days and 2 are due to leave next week. Because of the possibility of extra work I have offered to extend the notice period to these 2 for 1 month whilst we see if the new work materialises. The employee moving to days has agreed to stay on nights, 1 of the leavers has agreed to stay on but the third will not extend. He has worked for less than 2 years. The reason he was selected for redundancy was because, for personal reasons, he cannot work days. He was made redundant because we were closing down the night shift and could not offer him alternative employment that he could do at night. He was offered a job on days as he is very good at his job. My concern is that if he leaves next week and I continue to run my night shift for 1 month but then possibly longer if new work continues to appear will he have a case against me because I made him redundant due to nights closing and then in fact they don't? Am I better off just closing nights, proceeding as original plan and turning any extra work away? He is a really nice guy and understandably stressed with this situation. He is a good worker and has done nothing wrong but is now talking about unions, court and tribunals. Financially things are very very tough and I can't afford to make a mistake and get taken to court. Any advice great fully received. Thanks.

Can I check I have this right?

He can't work days for personal reasons. You were ending the night shift so he was made redundant. You offered him days but he said no.

Things are now looking better and you are now extending the night shift for a month and have offered it to him. He has said no.

Obviously I can't tell from what you've said whether there have been any mistakes to date, given he is talking about tribunals, but based on the facts above, I can't see there is a problem extending things for a month as long as you offer it to him.

He only has 3 months to claim unfair dismissal. So as long as you offer him the extension as you have done, and then if things change within that time you make sure you offer him employment, I can't see there's a problem. Just keep communicating with him. It's fine if things change, so as long as he is given the option of staying, you should be fine.

Thanks for that. I have decided that it is not worth the agro and the new work was not great margin anyway. I have told all the staff being made redundant that the redundancies stand. I have been so careful to do things the right way - it is such a long painful procedure and I would be so cross to fall over at the last hurdle. Thanks again.