Sorry to hear that MBH.
For what it's worth, when I was made redundant a couple of years ago I was advised to take legal advice and told that a certain (not particularly large admittedly) amount of that would be covered. I don't know if that was because it was a legal requirement that they do that, or if my firm were just being generous. If there is someone suitable you have contact with, you could ask this. Otherwise my first step would be to go to a Citizen's Advice bureau.
Of course you are likely to be told more about the process at the consultation meeting - it isn't necessarily aimed at you trying to make them change their minds, but more to tell you what is happening and what it is likely to mean for you. We didn't have a consultation meeting as such but I think that was because we were only a small office and I believe the necessity for a consultation meeting kicks in above a certain size of organisation.
There should also be info you could find on the internet, in particular about the whole process, but for advice specific for you you would need to talk to someone privately.
edit, I see I have spent too long typing this and CAB has already been suggested. I don't however think that lump sums are deductible from other benefits. And up to a certain amount they aren't taxable either. The only way I think they might affect benefits if is they bring your savings over a certain level. But I am not an expert either - so get advice from someone who is!!
