if "Lodged by" and "Signed by" both are connected to the people app you should see in the dropdown list of the calculation field 2 times  All of ContractID and Title - via Lodged By and via Signed By (both incoming). When you type @all of ... and the list pops up, go on typing the complete field name, then you should see both vias (while typing more and more the list gets more and more specific).
var lodged = @All of ContractID and Title.length;
var signed = @All of ContractID and Title.length;
The token for var lodged must be picked from "via Logded By", the token for var signed from the other via.
if you want the sum:
lodged + signed
If you want to show each with it's own number:
"Lodged by: " + lodged + "\n" + "Signed by: " + signed