I thought I had got my head round this, but either I have forgotten what I knew, or I never really understood this. Bear with me

Before I bought my sheep in April, I got a holding number.
When I got the sheep I sent off the movement records (it was just after the change but they said this was fine).
A nice lady called me (unfortunately I do not know where from) to check that I was happy with everything I had to do for movement records, meds records etc. She said at the time that I had a flock number (and even read it out to me). I told her that I didn't have this before and she said that it was probably on it's way.
Now my memory is really quite bad so I forgot all about this until now.
I am now looking to introduce my girls to their new fella. They are registered Ryelands.
So my questions are; what is the flock number I should have received and who do I need to contact to get this (England)?
Do I need to inform anyone (RBST?) that I intend to breed the Ryelands so that I can register the lambs, or do I just wait until they're born?
Sorry if these are daft questions