Hi there, to answer your questions:
1. Can they force me to sign the new contract in any way?
No they cannot force you to sign it but they can try and force the contract through anyway even I you do not agree to it
2. Can they terminate my employment if I do not sign the new contract?
Potentially yes but it is unlikely to be considered fair from a legal perspective. Instead they may terminate your current contract by giving you notice of termination then re-employ you straight away on the new contract, so which technically it would be a dismissal you would remain in a job but under the new terms.
3. Can they make me redundant if I do not sign the new contract?
Not unless there is a genuine redundancy situation
4. If I sign the new contract will my 3 month probation period (1 week notice) start again?
Depends on what the terms of the contract are, but you will have 2+ years service with them so legally they cannot give you less than 2 weeks notice anyway. You can try and negotiate a longer notice period without the need for probation
5. The short contract refers to a very detailed company employment handbook on a company server which can change at any moment, is that legal?
Yes it can be, policies and procedures can change from time to time
6. Is 3 days a reasonable time to review the document? They have said I can use some of my work hours.
Legally there is no defined period for this, so they could say 3 days or they could decide it has to be sooner if needed.
I hope this has answered your query. I would be grateful if you could please take a second to leave a positive rating (3, 4 or 5 stars) as that is an important part of our process and recognises the time I have spent assisting you. If you need me to clarify anything before you go - please get back to me on here and I will assist further as best as I can. Thank you