[Bug]: Post-processing script when calliper names have spaces

### Contact Details

jed.baker@metoffice.gov.uk

### Are there any linked Issues or Pull Requests?

_No response_

### What happened?

@MetBenjaminWent discovered that any spaces in calliper names will break the script. This needs to be fixed to allow for any calliper name to be properly processed.

### Version

main

### Relevant log output

```shell

```