had a few close missis with locking bolts on renaults just starting to round off as they are being loosened so form now irrespective of what car they go on slightly less torque...
and one of the first jobs i do when i get a new or different car
cup vs non cup difference only spring and dampers + anti-roll bar and on 200 steering rack (as in its quicker) suspension wise...and later cars have different top mounts
i have dealt with millers direct with regards oil supply at work...top set of guys and they know their stuff!
ps used the ee nanodrive oil 0w20 gf 6a in the yaris
clean off with brake cleaner and check after a few days if it comes back just take the bolt out clean off and a smear of rtv under the bolt head and refit
i suppose it could be the issue...dont work at the engine shop anymore so not got access to the data on head gaskets
2 options take it back to them to fix correctly or take the head off and have a look...
slight clue here...still the k9k engine...if that pipe is disconnected and engine spun over should be oil there if not then need further investigation..