Thanks all for your views – given the unanimous view that a postal survey is not a good idea I’ll re-think this.
As Bob Cole suggested, taking my customers out to lunch is not an appropriate route for me (I think there is probably a difference in UK and US practice, added to which my clients are in the public sector and might find it difficult to accept an invite like that). I do already seek feedback either face-to-face or over the phone. I had two thoughts in my mind when I considered supplementing this feedback with a form to be e-mailed back – one is that some clients might find it easier to give feedback about things they didn’t like in a more impersonal way, rather than directly (and I want to hear about the things they didn’t like as much as the things they did, so I can do something about it and win their future business). The second is that it would be easy to include a box for testimonials that they would be happy for me to quote (while being free to leave the box blank if they prefer).
The point about people being busy, and not seeing anything in it for them, is a good one though and I’ll think about that some more.
I appreciate the advice, and thanks again to all.
Stuart Reid