Bootcamp partition lost after update to Catalina

I have a MacBook Air (2015) with Bootcamp which I use to run windows. MacOS updated to Catalina (10.15.4) and now I can't boot into Windows. It doesn't show up in startup disk or when I hold down alt/option during boot. The partition also wasn't visible in the Disk Utility.

I have been trying to follow some of the threads answered by Loner T such https://discussions.apple.com/thread/8369480?page=1. The details in that post matched my situation so I followed the instruction in Internet Recovery mode:

diskutil unmount disk0

gpt add -i 3 -b xxxxx -s yyyyyyyy -t windows /dev/disk0

diskutil repairDisk disk0

with the relevant numbers

That bought the partition back into disk utility but greyed out:

I then tried testdisk and got to this stage: https://discussions.apple.com/thread/7275705?answerId=29089993022#29089993022 then hit and error when I pressed p:

I'd be grateful for any advice on where to go next. Do I keep pushing with testdisk or try another method?

Outputs to commonly recommended commands:

Thanks