Incorrect removing duplicate donations from the same person

[ajparsons]

We currently for the excel sheet group based on the free_text of an interest, to show the first and last time it appeared.

The assumption there are no duplicate freetexts in the same register for a person. This isn't true - and the better data validation makes it easier for things to be declared exactly the same twice.

(Some of these might be reporting duplicates, but are assigned different ids in parliament).

So when grouping, we need to keep these somehow.

Possible approach:

• When looking at individual registers, assign an additional 'dup_number' based on the same text and person_id.
• Then when adding up group on person, free_text, dup_number - which will in most cases be 1.

Order shouldn't matter here.