Here is what *The Cambridge Grammar of English* (p242) has to say on this issue:

> When the copula is cliticised to the subject in informal style, many
> speakers use the third-person singular form irrespective of the number
> of the post-verbal NP. *There's only two problems remaining.* This
> pattern suggests the verb agreement is simply with *there*, treated as a
> 3rd person singular pronoun like *it*.
> 
> When the copula is pronounced as a full independent word, the
> person-number properties of the verb match those of the post-verbal NP
> ... .

So it appears that following the clicticised *is* in *there's* with a plural noun is not uncommon in informal language. It suggests that the TV presenter said: *There's only two episodes left*, not *There is only two episodes left*.