I did my CBT the very 1st year it was introduced. Having ridden for years before I spent a lot of time standing around waiting for newbies to complete the tasks. Our instructor was constantly apologising to me and said that he should have booked me in with another group that had similar history & that it was a learning experience for him as well. I was patient & didn’t complain. Half way through the road section I realised that the radio had gone a bit quiet so pulled over ( I was lead bike ), after a few more minutes I heard him tell me to make it back to the test centre ( pub car park ), it transpired that someone in the group failed to negotiate a roundabout & binned it ( luckily no real harm done ) & I rode pillion to pick up the stricken bike. Had a long chat with him afterwards about lots of stuff such as the suitability of a potholed pub car park strewn with gravel as a first experience for newbies. He took my comments on board even rewarding me with a free post test advanced riding session ( smug or what!! ) If all establishments were as switched on as him, I’m sure you would have had a different experience. As has already been said, discuss your previous experience, you don’t have to say it was with the same outfit, and most importantly don’t ever, ever give up.