I bought a precooked ham from M&S food to order but didn’t end up having it on Christmas Day. I just checked to see when it’s Use By date was and it doesn’t have one on the ham. It says check the box but the box was the brown cardboard the order arrived it and I threw it away. So any guesses on how long a precooked vacuum packed ham lasts? It’s not been opened. It’s the winter citrus spiced ham joint. Any help much appreciated!