Hey Matt,
Thanks for the response. We've been using the null option as a workaround but this was failing on that specific attribute, equally we've had to use %00 to equal null for multi value attributes.
In this specific case the phone number attribute had a regex in there to specific numeric only. The regex however didn't have an OR in it for empty string, hence once you'd set a value you couldn't delete it with a blank string.
So the problems not quite resolved as we still don't know the delete syntax but we do have a work around!
Thanks,
Pete.
