[Baz]

I read the entire thread.

If it were me, I'd set a price for copies of existing surveys to cover your time and trouble and make sure it is published on your business website, listed with your 'services offered' documents, as well as in a posted sign format hanging in your office - for all to see.

Someone starts squawking - just point to the sign.

Have no idea what to charge - that's up to you.

You can always waive the fee for those who "take care of you".