Basically the result of the code originally posted goes to a custom property type ‘string’ which I then filter using three more custom properties (all expressions using the replace function to get rid of all [] and , the end result is used in a SQL query to populate a tables data. This SQL query was where the error came as no columns were called u’Mains’, u’water’ …etc, hence the need to suddenly add a fourth replace expression to get rid of the newly appearing U’s.
I guess my whole method is too basic and the sort of thing a beginner would do but I just wanted to understand why a 3 month old screen suddendly went bad so as to avoid the same in future work.