Hopefully this helps someone!
Went for my coil to be removed and a new one fitted today. They asked me a few questions to start and did my height, weight, BP, and a urine sample. The appointment coincided with a v heavy period so I wanted to check that was ok (it was)
This is number 4 for me, I've always had 5 year copper ones but they did a 10 year one today
She did a quick exam to check where my cervix was and then used instilligel (local anaesthetic gel) on my cervix which gave me some cramps. Then my old one came out (felt a bit weird) and they let the gel sit for a bit
She held my cervix still (only sore when she first put the clamp thing on) and then did the sound (measuring my womb) which wasn't actually painful at all this time. I was having cramps from both my period and the fitting but not severe. She inserted the new coil which was uncomfortable and made me say ow but not excruciating. Then did a quick ultrasound to check everything was in place
Then because it had all gone so well, my body decided now was the time for my blood pressure to crash 
and I went faint and hot. They redid my BP and turned a fan on me and I had some lucozade in my bag. Didn't work so they put the head of the bed down so my legs were right up and after about 15 mins I felt loads better and just had to sit in the waiting area for ten minutes before I drove home