By chance I noticed a contact had an old number. So I edited it. The pic appeared!
So been playing, if I go into a contact and change a number, the pic appears. Selecting edit and saving without changing a number DOESN'T work. I must change a number. So been changing some to +64 and others to 02 etc. Works everytime. Adding an email etc doesnt work. Has to be a phone number. Haven't tried a non mobile number yet.