I hate to sound a note of caution here but:
First of all, any airline interview I have ever done I was asked whether I have EVER failed a check ride (at least here in the US it is a standard question), at that point you will have to talk about this experience. Most people will have had some problem along the way and it's no biggie, however, the first thing we MUST learn along the way as pilots is HOW to pass check rides.
There are some things that are laid out for the examiner that will result in automatic failures: land before threshold, descend below MDA (even 10 feet) on approach (before rway environment in sight etc), taxi onto a runway w/o clearance etc. All these things are important and serious safety considerations, I don't think anyone would (or should) pass a checkride with a mistake like that. Maybe some focus on the essential elements to pass your checkrides might be key. Additionally, if the examiner has to take over control of the aircraft then that should be an automatic fail also.
The more serious consideration for me is the very fact that you think it's not a big deal to land on a taxiway prior to the runway threshold or get so close that the examiner has to take control and makes me wonder if there are some grave attitude problems. Failing to go-around TWICE. You have to realize that examiners don't care as much whether you can "make" the landing as whether you are safe.
If you were my student (when I was a flght instructor) and you gave me that explanation (ONLY 3m before threshold etc.) I would feel that I have utterly failed and would ask another FI to take you over.
Sorry if I sound a little harsh but I feel an honest point of view might be of more use to you than just more words of encouragement.