Thanks, appreciate the responses. I'm sure you're right. I've obviously e-mailed the fitter to check, but wondered if anyone had any experience of long-term use of an "adjustable" / ex-demo head in this way.
I'm buying the head and will take it along to my fitter to get it matched with the correct shaft, lie adjusted etc etc.
The issue is Mizuno don't make the JPX 921s any more, so the fitter was struggling to find a head (esp. being a leftie).
So, my question is: Assuming that I can get the shaft...
I lost my 7i and would like to order a replacement head from eBay.
Is there any issue with ordering an ex-demo head that has the screw in the back for easy shaft switching? I had my irons custom made and I notice that they don't have the demo club screw, so would there be any issue with using one?