Not true....The MOT test centre down the road fail cars with no DPF or cat all the time.
Its too much of a risk not to. The ministry send in cars under fake names all the time with faults to check them out. Pass a car that should have failed and they could lose their licence,...and since hes MOTs only that would be bad news!! I think you would need to be on first name terms with the tester for them to risk it now days. You will always get some that will pass any old crap though......up to them.
EGR and adblue deletes cant be tested for if its just been mapped out....so you are OK there.
At the end of the day this kit is fitted to cars for a reason.....BECAUSE ITS THE LAW......so if you get caught without it and get the £1000 fine or they void your insurance after a crash then I have no sympathy for you.
Official advice and information about MOT testing from the Driver and Vehicle Standards Agency (DVSA).
mattersoftesting.blog.gov.uk