Hi sorry I was going offline when I picked up your query last night which is why I could not reply. It is entirely legal for the employer to make the proposed changes to your contract if this is as a result of a redundancy situation. In effect they can remove the permanent role you are currently doing and replace it with whatever they see is required, such as a temporary one or one with less pay.
As part of the redundancy procedure, the employer must offer you suitable alternative employment to try and avoid having to make you redundant. So in the circumstances they could offer you the newly created role as a suitable alternative for you to decide whether you want to take it up.
If the offer is considered unsuitable and the employee refuses it, they will be made redundant and still receive redundancy pay. However, if the offer was suitable and the employee unreasonably refuses it, they would effectively be resigning and will lose their entitlement to redundancy pay.
In the circumstances you can argue that the role is unsuitable due to the reduced pay and the temporary nature of it. You can refuse it and be made redundant but if you accept it then you will not be being made redundant and will simply continue working in the new role without being entitled to any redundancy.
This is your basic legal position. I have more detailed advice for you in terms of the law on suitable alternatives, trial periods in the new job and your general rights in that case, which I wish to discuss so please take a second to leave a positive rating for the service so far (by selecting 3, 4 or 5 stars) and I can continue with that and answer any further questions you may have. Don’t worry, there is no extra cost and leaving a rating will not close the question and we can continue this discussion. Thank you