"There's a big old voice on her!"
I blinked, because AFAIK that was pure Wenglish
Nobody - not the other presenter or the guests - had any problems with it, but I started wondering:
- Would all inhabitants of the UK from outside Wales understand exactly what she was saying?
- Would inhabitants of other English-speaking countries understand it?
- Would people who had learned English as another language understand?
So, what do you think she meant? I'll update later with a translation.
ETA: "What an enormous voice she has!" or "She has such an enormous voice!"
Much as I suspected, you focussed on the vocabulary aspects, but what caught my attention was the sentence structure.
"There's" is used a lot in Wenglish, but not in the usual sense::
"There's lovely!" "There's daft you are!"
What you should by now have noticed is that "has" is absent from the original sentence; replacement by a preposition is quite common in Wenglish, taken from Welsh, as Welsh has no verb "to have". It is usually replaced by words for "with"; it was a bit naughty to use "on" because "ar" is normally used for possession on a temporary basis. But Wenglish is not as consistent about this as Welsh is..
"Old" as an intensifier is not exclusive to Wenglish, at least I don't think so (a little later the weather forecaster referred to "some strong old winds") but it's less common in other dialects.