As you have already found out, Coot has recentering commands.
Here is a step by step for future reference:
First activate the cryoEM module, if it isn’t already:
Calculate → Modules → CryoEM
then
CryoEM → Go To Map Molecule Middle
or:
CryoEm → Go to Box Middle
will take the cursor in the middle of your electron density, or box (usually the same place)