Will I be forced to cover for redundant colleagues on return from maternity leave?

I am going back to work later this year and had already confirmed in writing my intended plan and to go back three days a week using my accrued holiday. I was told that they would discuss and get back to me. A month later and I chased, having heard nothing, to find there was a company meeting they had forgotten to invite me to, but that they would ring and update me. The upshot of this call was that people in my team were being made redundant and that they want me to go in in two weeks to discuss my restructured role on the back of this. I know they are getting rid of my colleague who does the other half of my similar workload and my assistant so I am pretty sure they are about to try and push a load more work on me on my return. There is a lot of advice given for if you are made redundant while on maternity, but what happens if you are expected to take on more when you return. I have no problem working hard, but feel I do not want to go back into a job where I am overworked doing two people’s jobs due to them making my male higher paid colleague redundant while I was off. I feel I would have liked to be consulted before the decision was made as I might have volunteered for redundancy myself rather than be pressured into taking a increased role, especially when I was hoping to work three days a week when I return. What rights do I have in all this?