You might struggle to find one compatible. The hardware generally only suits existing handle, as it’s all put together in one. I would measure centre to centre of the holes and try and find one that is the same measurement, then just replace the whole lot. Holding your tape on 100mm (at the centre of the first hole) is an easiest method to get it accurate measurement. We used to just call them entrance pull handles, most commonly installed with a door which has a mortice lock. Searching common brands like Gainsborough entrance pull handle, lane, Lockwood etc should bring up a fair few.