I had it done last time but not this time.
Why are you having a canula? Did you have PPH last time round?
I was wondering exactly that. You are not in grand-multi territory yet so unless there is something else pre-disposing you to PPH, I am not understanding why you are getting a canula.

If you do agree to it for pph purposes, my advice would be to not let them attach synto unless your loss becomes a concern (over 800mls for SVB). I only say this because I know from experience that the uterus contracting with synto can be just as painful afterwards as it is during an induction. To me it feels like I am still in labour.