Do not remember seeing it on the drive when I started the job, but just before refit I noticed it amongst the tools and coolant rail on the floor. Sounds like it might just be coincidence. 7 always parked in that spot though so strange it should be there. All working well without it, After reading several posts on coolant rail leaks I did file the flange flat, and checked for distortion when fitting the front bolt (no washers needed though).