|Ok, think Ive fixed it by deleting the keys IconStreams and PastIconsStreams under HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\TrayNotify.|
Then rebooted. This seemed to get all the icons showing again. But the chevron icon of the Hide Icons still wouldnt show up, even after unticking then ticking the Hide Inactive Icons in the taskbar properties. But clicking the Show Desktop icon in the quick start tray on the left seemed to get the chevron back.
No idea why, but thats Microsoft for you. Hope this helps others.
Edit: I havent tried a reboot yet after the Show Desktop but Ill report back if it hadnt worked.
Edit2: Nope, didnt work. The icons seemed to revert back to not showing some of the icons even after deleteing those registry keys again. Show Dekstop has no affect anymore on getting the chevron to appear.
Edit3: Seems the icons appear ok if have SSDP Discovery Service disabled. No sign of the chevron tho still.