flooring insulation

Guys can you just confim that these missing bits of floorboards should have been replaced with some new sections of pine planks with the same thickness and grade... New flat who ever installed the new heating system butchered the old floor then juat walked away no idea what he did with the...

Hi everyone, I've a 7x3m concrete base that I need to frame and insulate but I'm seeing general pir sizes are 60, 80, 100mm but the timber merchant on supplies 95mm. Should I be using 95mm timber and 75mm PIR with a gap underneath instead? I kinda wanted 100mm in there though. Thanks!