Welcome to Answerbank.
As you've discovered Answerbank isn't very user friendly for new posters because of:
(1) the badly designed layout which has a SUBMIT button immediately after the Title box rather than after the Question Details box; and
(2) as soon as we press enter or return our question is submitted.
CBT = compulsory basic training (required to ride a motorbike)
Yes it will invalidate your insurance, most insurances include a clause that you need the correct license for the vehicle insured. the insurance company may pay out third party costs in the event of a claim but then they would recover the costs from you.