If we don't find a document for e.g. March 2018, then would February 2018 suffice? It's a bit unclear to me how exact these document timelines have to be. If it has to be at least every 4 months, then perhaps we could supply another document in eg May 2018 to not have the gap betwen February and July being over 4 months.
The documents should be spaced evenly, every 4 months. The gap between each document should be 4 months. If you have individually addressed documents, you need 1 each from the same month, preferably dated within a few days of each other.
So, you really need 1 document in each name from each of the following months only:
July 2018
November 2018
March 2018
July 2019
November 2019
March 2020
(July 2020)
If you are unable to provide documents dated every 4 months, or you can't provide the right number or sources of document, you need to write a letter explaining the reason(s) for this.
If you can list all the documents you have, with the exact dates they were issued, and which name(s) they are in, we can help you work out which ones you can use for the requirement
.