Closes #181 Assertion added for cut date not to be NULL #181

[barnett11]

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[github-actions]

Package	Line Rate	Health
datacutr	100%	✔
Summary	100% (389 / 389)	✔

[barnett11]

There is a pull request warning for updating roxygen2. I am struggling to do it, and given it is not important and has other knock on impacts, we will ignore for this release and investigate post release (as it does not impact the package directlty)

[alanaharris22]

Thanks Tim, looks good.