I agree with what was said above. The only thing that I would advise is to take or pre place your own sanitary pad into the underwear you wear to the colposcopy. I bled a substantial amount after the biopsies and wish I didn't have to fumble around placing the sanitary pad on (it was a hospital one! practically a nappy in my opinion!) after the procedure as I was a bit shaky and there was blood running down my legs and it was all just a bit traumatic. Particularly because I wasn’t as smart as you to ask what to expect after the procedure nor was a told anything from the doctor’s office (I am in a different country so don’t worry about the NHS service level)
By the sounds of it, I bled a lot more than others so hope I don’t freak you out. The procedure is not painful; however, I definitely felt her taking the biopsies but almost the same pain level as having an injection in my opinion. The emotional aspects are definitely the worst of the procedure.
After the procedure I was a little saw for 2-3 days but then felt normal other than the bleeding. Something I also wasn’t told after the procedure is to expect a tissue like clump to come out as well as small blood clots. The tissue like clump came out at the end of the second day for me whilst I was wiping with TP ;) sorry if TMI. It apparently is the scab part of the cervix and the mixture of liquid they apply to the cervix in the procedure.
Hope this helps, just small tips and overall a very simple procedure. Best of luck for a fast road to clearing the CIN3.