Vamps, glad you have kept your job and I'm sorry to hear about your colleagues. I would suggest that those that are having to reapply for their jobs, get their CV's out in the market and apply for other jobs, so they might get another job or some interviews lined up before the 23rd December. Even if they then hear the worst then they psychologically will have other irons in the fire, to cushion the blow and hopefully make the best of a bad situation at Christmas. Hopefully, some will find alternative employment, a better job and employer.
I've only an old copy of Tolley's Employment Handbook so this might be out of date.
If more than 20 people are being made redundant then there must be a consultation period with employee representatives. Are more than 20 being made redundant?
IMHO handing people envelopes instead of having a personal meeting is a cowardly way of handing things. To me, the very worst thing of being an employer in the past was making people redundant, having to get rid of very good people was hard, but the alternative would have been worse, bankruptcy and everybody losing their job.

I always did this with a personal meeting and would explain why such a sad action was necessary and to personally thank them for all their hard work.