Hi Duffryn,
When I bought my Gen4 Prius, I remember telling the salesman that if the number plate had an EU flag on it I wouldn’t accept the car! As it is they made sure there was no awful EU flag, but it’s refreshing to read that I’m not the only one that doesn’t want this almost ‘imposed’ flag on my plate!!
I my case only the bottom hinge had come away from the glass so I left in in place but used a couple of clamps while the glue dried (door will need to remain open).
Hi, try checking the Crankshaft Oil Control Valve (OCV) connector. I think it's on front right as you look from front of engine, attached to cylinder head.