I should find exactly the post but :-)
I did the vent covers what some say is the short way and posted pictures. I said I was of to do about 2000 miles in France much at fast motorway speeds. Well I got back after near 2500 miles and was a bit busy so with 3000 miles I can report 100% fix
I took pictures to post but I am suffering brain fade and can't remember how to post them here.
To recap I took the breather covers off spent ages cleaning off all the old RTV the re RTVed the covers and fitted them. Then the important bit allowed a 24hr cure/dry time.
3000 fun miles later no hint of any leak, nothing. The cleaning and dry time are very important.