@Sunnyday123456 Talk to HR about options. I was CS so not dissimilar to NHS and my advice would be to go part time on return from mat leave and use annual leave (earned full time). However, parental leave might also work.
Assuming you accrue a full year of 29 + 8 days you have 37 days which is 7 weeks 2 days leave. 3 months is 13 weeks.
Option 1 - part time
Ask to be redeployed on health grounds to a part time post - 37 days @ 7.5 hours =277.5 hours /13 weeks =21 hours 20 minutes a week. So reduce to 3 x 7 hours.
Option 2 - part time but work some days
Again ask to be redeployed and reduce to 3 x 7.5 hours = 22.5 a week and work 2 days.
Option 3 - full time and work some days
Stay working 5 days but use 3 days leave each week (3 x 13 = 39 days leave) except for 2 weeks when you work 4 days or 4 weeks working 3 days.
Option 4 - use parental leave
Split the 4 weeks into single weeks so weeks 1, 4, 7 and 11 take as unpaid parental leave. 37 days annual leave covers weeks 2, 3 (10 days leave) in full and for weeks 5, 6, 8, 9, 10 and 12 take 4 days and work 1 day (24 days leave). Week 13 take 3 days leave and work 2 days. This way you spread the unpaid leave over several months.
These are just quick thoughts, be creative about what you can (and want ) to work.