switch date lookup table

[alee5646]

Summary

Files updated:

Reason for change: What was the problem?

Changes made:

- changed lookup table to allow for data to be taken from 2003

Checks for creator

Delete all non-relevant lines below, and then tick off as completed:

• [ x] I have run the code in the scripts I have changed
• [ x] I have run the relevant run_data/run_tables file
• [ x] I have included comments to explain my code
• [ x] I have checked the layout of the code is logical and easy to follow

Closing issues

Replace the XXX with the issue numbers for any issues that can now be closed:

Close #XXX

Checks for reviewer

Creator - delete any not relevant. Reviewer - tick as completed:

• I have run the code in the scripts that have changed
• I have run the relevant run_data/run_tables file
• I have checked the layout of the code is logical and easy to follow
• I have checked new variables are named consistently
• I have checked the list of github issues