Improve where clause?

[stufraser1]

Further tests and fix required:
Can converter run successfully with a 'when:' clause and a fall-back transformation, either with or without another alternative 'when:' condition?

Ascot testing showed it transforms the field successfully transformation with a when: clause and apply it only to the correct subset, but I can’t get it to fall back to another transformation for those rows where the when: clause evaluates to false.

Line 152 of mapping yaml:
- transformation: Limit1
when: IsLayer is 'Y'
- transformation: SubLimitOcc

Here Limit1 gets pulled through correctly for the rows where IsLayer = Y, but the rows (with IsLayer = ’’) which should be SubLimOcc are coming through as blanks instead.
User should be able to string many conditionals together but it doesn’t seem to work (or will pick up only the first transformation).

[stufraser1]

User guide also needs to include practical examples of how to use when clauses, to assist users clearly (feedback shows users don't know what is possible yet).