Yes. There is no law or principle of democracy that says a topic can only ever be voted on once.
There are many examples of repeat referendums on the same issue in democratic countries - the UK on Europe in 1975 and 2016, Scotland on devolution in 1979 and 1997, Quebec on independence in 1980 and 1995, and Ireland and Denmark on EU treaties.
What is required for a second referendum is not permission from the first result, but a new democratic and legal mandate - usually a new Act of Parliament and, in the UK context, agreement on the process for holding it.
In short: a referendum settles a question for that moment. Democracy is what allows that question to be revisited in the future if the people, through democratic means, choose to do so.