I've been told that if the town/city begins with a vowel the 'à' changes to 'en'. Is that right?

Bonjour Anne ! I'm afraid you're mixing two different lessons :) To say "in/to" + city, you always use "à", regardless of spelling. But it's a different matter when it comes to countries, or regions/states... Here are links to our related lessons: Using en with feminine countries and au(x) with masculine countries to say in or to (prepositions) En, dans = In, to with regions, states, counties (prepositions) I hope it helps! À bientôt !