BTEC Science (new). Is this considered a "re-sit"?

Is re-doing a BTEC course considered a "re-sit" if you already have the subsidiary diploma

Last course year (2017/2018) I was doing a BTEC Extended Diploma course in Applied Science - the one that is 2 years long and has units that are externally assessed, I left only months after being on the course due to some issues that came up, it was after I done the unit 1 exam and unit 3 exam practical/written (I passed them all), plus another whole unit that contained a few assignments. I didn't finish doing all the assignments for the units given on the first year. When had to leave the course I got told by one of the teachers that I had already achieved the subsidiary diploma, but I am nearly sure that was only to convince me to stay on the course because I had not finished all the assignments that I was meant to finish for the first year.
In this course year (2018/2019) I enrolled for a BTEC National Foundation Diploma in Applied Science in a different college - the qualification that last only 1 year and has two units that are externally assessed. This time I will be able to stay on the course and finish. It's another college and I have not told them that in the past year I was on a BTEC course doing science and that I had done unit 1 and unit 3 exams, I was too worried about being refused.
Is what I am doing considered a "re-sit"? If so I will have to let my new tutor know and pay for the extra exam fee, that isn't a problem but it's a very very very bad thing that I haven't let him know.
Is what I am currently doing allowed in this new BTEC with external assessment qualifications? I will be doing unit 1 and unit 3 again.
I have emailed BTEC about this but the answer I got was not clear, I guess I got them confused.