You should be able to delete the backup file(s) provided you can identify it/them positively. If you used Acronis, this will be simple but for any other backup software it may prove more difficult.
A simpler method may be to go to the manufacturers web site and determine (perhaps via their Help Forum - if they have one) what files constitute the `D: Recovery` partition normally and delete any others that are present. I would hope the essential files in D: for recovery would be `Read Only`.
Failing that back the whole partition up onto an external HDD and then delete those files you believe to be the backups. That way you have a copy in the event you get it wrong.