Only full-time jobs available in restructure

I was TUPE’d to a new employer in May 2017 following a contract change. There was initially a very unsettled period following this where there was talk of restructure affecting my grade only. After several months of anxiety and unknowns we were given written confirmation that we were no longer at risk and that our jobs were secure. Based on this I made the decision to submit a flexible working application and reduced my hours from 37 to 22 per week. Less than six months later we are now being told that they are going to restructure and that there will be five full-time positions available. Those five who are not selected will be made redundant. This process is going to be very quick. Having given up my daughter’s space at nursery and my son having started school I am now not in a position to immediately apply for a full-time position. This seems to leave me with no choice but redundancy,. Can my employer do this?