In modern British punctuation, the full stop (period) is used when the last letter of the abbreviation is missing, as in etc. (etcetera), ed. (editor), Prof. (Professor), but not when the last letter is included, as in eds (editors), Ltd (Limited), Dr (Doctor).

As for taste - when I was a child I loved Tizer. It had a pleasing, slightly caramel-like taste. I tried it recently and it was just horribly sweet. Has Tizer changed or is it just me?