on my project 2.0, the cam cover seemed very loose without this bolt, BUT.. felt OK with the tray clipped in, I'd have happily driven it.
I think I may have one of those bolts on my Donor car if you need one... free to a good home such as yours Tunnie 
Sweet, cheers for that James.
Just out of interest James, did you project 2.0 have a gap were the nut was supposed to be? I.E a whole were crud could get in?
Like you i think the top clips will hold the cover nice and firm, its just that back plate. Tempted to WD40 it today, and try tomorrow for the best. IF it comes out then off to the scrappy to see if that facelift 2.0 wreck is still there...
Also just realised supposed to be meeting old friends on saturday.
If i can get it out tomorrow then great, i'll replace it. However if its going to be a git, i think i will leave it re-assemble, and then take it for a good hard run on Friday. I mean a really hard run, make sure that plate won't become loose, also make sure the new coolant does its job

Then friday afternoon pop the cover off again, and check the plate and condition behind there.