You have a working relationship with your instructor and it should be a two-way process. If he thinks you are not ready, he should tell you why, without you having to ask. Going on a rant is not usually a good way of convincing a pupil that they are not ready.
Can I throw a couple of other considerations into the discussion? Right or wrong, as instructors we are taught that the only way to 'control' test timing is to withdraw the use of the car. If a pupil tells us when they are taking their test and we don't agree then, unfortunately, sometimes we have to withdraw use of the vehicle. Our responsibility is to produce good, safe drivers, not someone who can propel the car from A to B, learn the test routes and fluke a 35 minute driving test. The test is an imperfect instrument and it is possible to pass when you are not as safe as you need to be - I know this to my cost!
When I take pupils on a mock test and ask them how they got on, more often than not they identify some of the faults they committed and on the basis of those faults, it probably would have been a pass. However, very often they have completely missed the really dangerous things that they have done because they are completely unaware of the chaos they have caused. These are the issues that I and many other instructors work so hard to eliminate because these are the ones that are so serious.
As far as your situation is concerned, I would ask your instructor what aspects of your driving need to be improved. That is not dictating to them how to do their job. If they can't or won't tell you, then they may be trying to delay unnecessarily. If they can then it is possible that they are seeing something that you are missing. You are employing them as an expert in their field - ignoring their advice seems a bit silly. Do you have a sheet charting your progress? If you do (and you should) then if that sheet is complete, you will be ready. If not, you will know what you still need to work on.
Finally, bear in mind that almost everyone thinks their driving is flawless, from the best instructor to the newest learner. Sometimes it needs a third party to do a correct evaluation.
It is impossible for anyone else to judge whether you should or shouldn't take your test based on your post. Taking an independent assessment is a good way to go so that another instructor can advise you based on the way that you actually drive.
Please don't think that I am doubting your ability to drive or your assessment of your own driving. I am not - just trying to put an alternative view which might affect your thinking. I hope that's okay.
Best Wishes
Emma