When you add a bank account to paypal it sets up the direct debit mandate so that paypal can take authorised payments for any purchases you make (or pay your Ebay fees). No company eg water/electric can take funds from your bank account on a regular basis without that direct debit. However the amount shown is always the ''last'' transaction / amount that you paid to a seller via paypal.
Advice is voluntary. Kudos / Solution appreciated.
