A script is not needed though that approach does work.
A calculation field with this expression will compute the elapsed days:
get ( CurrentDate ) - StartDate
This must be a field of type calculation and you must click the storage options button and specify that the field be unstored.
I'm sure that I tried that configuration at some points in my travails, however, it has solved my current problem.
No doubt I'll be back on the forum very soon with further queries.
Thanks you very. very much.