Does Champagne go off?

Same as wine. Some get better with age, some don't.

Drink it tongiht to be on the safe side ?

Depending on the quality it could be better for it. It certainly shouldnt have deteriorated too much.

Enjoy .....

It should be fine, but you will be able to tell when you open it - would be flat/smell vinegary etc

Drink it!?

I opened a bottle of Mumm that had been hanging around for about 5 years the other week and it was soooooooooo vile?

Wondered if you meant me for a minute! ?

I was given an expensive vintage Moet and didn't drink it for 10 years and it was fine. In future, store it on its side so the cork stays wet - this is what I was told during a champagne house tour.

The only advice I could find online is that you shouldn't really keep it 5 years +, and that you shouldn't keep it refrigerated for more than a couple of days as that affects the taste. I'm on the side of drinking it ?

Thanks all. I won't be drinking it tonight but probably in a couple of weeks.

Hopefully it will be ok.

Thanks again.