Carrier/cart/payment problems - resetting carriers possible?

[beyonceuk1]

Hi all. Running into big problems with our PS1.6 multistore set-up. All works fine except for orders paid for using either the ModuleMarket or Prestashop WorldPay modules where there is a new carrier set-up (or an old carrier is amended so PS give the carrier a new carrier ID in the database). Although the correct payment comes through, the order fails due to the carrier not being shown on the order (so it looks like the customer has overpaid by the value of the postage amount).

 

We're up to 300+ lines in the PS carrier table where we only use around 10 carriers across all of our shops. What would the implications be of manually deleting carrier information from the database and setting everything up again? Any help would be massively appreciated!