Upgrade issues from 1.x to 2.x

Hi,

I'm trying to upgrade to 2.x from 1.x.beta-7. I have the latest https://www.drupal.org/project/commerce_discount module installed (alpha 4) and the database is up to date. On running coupon updates via update.php, I get the following exception:

DatabaseSchemaObjectExistsException: Table field_data_commerce_discount_reference already exists. in DatabaseSchema->createTable() (line 657 of /development_html/includes/database/schema.inc).

Having deleted this table in my test environment, the coupon updates seem to be re-adding it and then failing.

Any suggestions would be greatly appreciated.