Reverse lookup skipping blanks

[armchairandy]

I have two rows of data

the top row is either a number or a blank
The next row is a date, when the number was entered

This is carried out by the 1^st date being the project start & then all the other dates +7 days.
I have some vba that takes the date that the update is carried out on (always a Friday) and looks up the row of dates and pastes the update value against the date

5	Blank	Blank	Blank	8	Blank	Blank	Blank	10
07/09/18	14/09/18	21/09/18	28/09/18	05/10/18	12/10/18	19/10/18	26/10/18	02/11/18

<tbody>
</tbody>

I have a table on another sheet which lists the last 3 dates that data was entered - bear in mind that the periods between each date is a week, but the entry period will not be exactly 4 weeks apart

The table should look like

07/09/18	05/10/18	02/11/18
5	8	10

<tbody>
</tbody>

The 02/11/18 is easy as I can do a lookup based on when the last report was done (most current ie the report date)

what I then need is to be able to look from the number 10 leftwards & return the date & number of the previous update (ie 05/10/18 & 8), then the previous update (07/09/18 & 5)

Until now I have been trying to use the last date -28 & lookup the value based on the date, but this does not work when the update periods change.

The form is for multiple users, multiple projects, multiple update dates and needs to be automated so that mistakes/deliberate misinformation can be avoided.

The numbers can be negative as well as positive

Any help appreciated

Andrew