I Know how you feel Andy (or felt should I say) a few weeks back this happenef to me. We visited a 'Posh' restaurant in Southend called 'Tou Lou's' right on the sea-front, we were with friends and the meal was superb, service great, but at 2 o/c in the morning I was sooo ill, then it started again next day, on and off for 2days. I felt like death warmed up.
I put it down to the fish starter (no-one else had, no-one else ill) this was on the Sat eve. The following Friday I went in there to talk to the manager, He accepted full responcability, bowed and scraped & said the next time I was in there my meal would be on him. With this reaction it made me think I wasn't the first or only one to complain.
(I've never been back yet)
Jem