Hi all just posting my experience here for anyone worried.

Ok so there are nicer ways to spend a morning but it really wasn't that bad. Apart from anything else it's super quick, I'd be surprised if it took as long as three minutes.

Yes, I was gagging and retching most of the time (I have a strong gag reflex and slight emetophobia) but I've felt worse after too much booze! You can't actually be sick anyway, not only is your stomach empty but you lie on your side so that the saliva drains out of your mouth, the nurse also has a tube to suck it away, (like at the dentists). There's also another nurse helping you control your breathing - not sure how well I was doing with that to be honest but it is quite reassuring.

I think the worst thing was the taste of the throat spray afterwards - once the banana flavour disappears you're left with the real taste which is like antiseptic.

I now have some soreness under my ribs where she was poking around, a bruised feeling in my throat and lots of burping (which was one of my symptoms anyway) but otherwise all is good.