Long clean driving licence, no previous convictions and co-operation with the police will not save you frmo a driving ban if convicted of drink driving. Shortness of distance driven might (as it can be a Special Reason) but this depends on a variety of factors, in particular:
How far you intended to drive
How far you actually drove
Your reason for driving
and, most importantly, the risk of you coming into contact with other road users.
The case law on this is complicated and at times misleading. Only last week I represented a Defendant arguing shortness of distance driven when the court tried to impose the wrong legal test.
If you want more specific advice about your case then call us on 0845 0020736.