Thanks Mark, I've managed to set up the new field which would allow users to select the previous tariff from a drop down menu of all tariffs which relate to the appropriate supply.
Is there any way to create a field which would automatically populate the correct previous tariff? I would rather avoid users having to select it manually if at all possible.
I was thinking something along the lines of matching the current tariff start date with the previous tariff's end date (+1 day).
So if the current tariff has a start date of 1st Jan 16, the field would automatically find and populate with the tariff (for the same supply) which has an end date of (1st Jan 16 - 1 Day = 31st Dec 15).
Do you think this is feasible?
Thanks
