How do you go about getting sterilised

[incognitomosqiito]

I am 45 and just come off the coil due to migraines
I definitely do not want any more children

Start by seeing your GP to see if you can be referred on the NHS (and find out how long the wait in in your area).

If you don't get an acceptable pathway from them, the enquire of an organisation such as Marie Stopes about cost and availability privately

I suspect you will have a fight. Be prepared they will try and get you to try everything alternative you can think of.