Couple (or so) suggestions;
Make sure the ground connections to the chassis are clean and with good secure contact.
Make sure that the positive wire to the rectifier can't rub against the chassis, wear through and short out to earth. The first few inches of wire from the rectifier is prone to this.
Get a Harley Davidson or other third party compatible unit at greatly less cost and have it on the shelf (or in the boot) ready for the next time - much cheaper than one from MMC, just need to check that the crimped end that goes on to the main +ve connection under the bonnet is the right size for the connector.
The twin earth rectifier probably was a replacement!
