If you can drive safely, they will pass you. It’s that simple.
The only people who care whether or not you went car to CE is training providers. Pretty much all I approached wanted me to go Cat C to CE. One even tried fearmongering me saying how hard it is to drive a vehicle with airbrakes and how there’s a second or two delay when you press the pedal. Which was a load of nonsense, to get me into Cat C and do two tests.
Most training schools have their mates or ex-instructors partaking in comments to tell you how scary it is to go car to CE etc. All waffle back in the day most people went straight to CE without issue.
Others just specified I must do a driving assessment for £60, but were still hinting at going Cat C first and how large a CE is. It should all be at the discretion of your training provider after a few lessons or yourself if you’re really struggling with the CE, most issues will come in reverse. Driving a CE forward is a doddle.
Of course people making extra money off of you to do two tests will push you to make the maximum money option. 
When you’re paying £2700-3000+ for training you want to do one and get it done with. You can drive any HGV with the CE license most will be limited by employment options to drive a C1 at the start anyway.
The only part of the test examined by the DVSA is the road part now. A driving examiner will monitor you driving just like when you did your driving test. Reading your post again makes me thing you have training schools mixed up with a test centre, the latter will be operated by the DVSA. The first one is nothing more than a business providing training and a suitable vehicle for the test, which is nothing more than a business wanting to make maximum profit.