Thank you Stijloor, and it's true that the audit record can capture the data. The audit process can also provide enough insight to approach specific areas that need improvement, which a survey isn't likely to do unless it is administered scientifically. When I say scientifically, I mean in a way that identifies the department and shift of respondents. This can be done with codes placed in a corner of the survey, but people could be wise to this and shape their responses out of a sense they are being monitored.
I bring all this up because the business of assessing internal customer satisfaction is supposed to have a practical purpose. If an auditor views evidence the data are being collected, the next question will be (it had better be) "And what do you [the organization] do with these results?"
If your auditors don't prove to be the right vehicle for assessing internal customer satisfaction and your organization insists on a survey, Baldrige has a freely available survey you could consider:
Are We Making Progress? They even have an Access software download on that site--I have never used it, so I don't know how helpful it would be.
Even if you don't want to use that survey, its questions are, in my view, well constructed. Assuming (that's not dangerous, I hope) that people are happy when they are given everything they need to do their jobs, the survey could be considered to measure internal customer satisfaction. After all, it's about the success of transactions and their factors' design in the workplace.