Lisalisa - don't panic.
I don't think you'll be allowed to take your solicitor into that mtg, you can take a union rep or colleague - but be very careful with the latter and only use them as a witness not as a sounding board, their position is inevitably compromised.
Agree to NOTHING in the initial meeting. Simply listen to what they have to say, take notes and state that you will discuss with legal representation before responding to them. Don't agree or disagree to any proposals, just listen and state you'll come back to them.
Best case is probably to try to move to a compromise agreement rather than redundancy. During discussions you have every right to be in the office and even tho its the hardest thing possible I do recommend that you do this - 1) it freaks them out and makes them throw more cash your way and 2) you find out more about the history that can then be used in your case (for example when I was there they appointed 3 directors just after making me redundant which meant I could go for them big time but I wouldn't have known had they not been forced to meet me....)
Also when thinking about your package bear in mind things like getting to write your own reference, a clause that stops them saying anything negative about you, laptops, employment consultancy etc etc. You can barter any of your confidentiality clauses quite nicely here too. If you're not happy with your lawyer then I used a fantastic guy at Kennedys who I can put you in touch with.
Hang in there - its horrible and it takes a while to get over BUT it was probably the best thing that happened to me professionally now that the dust has cleared.