Did they film it in on the UK set I wonder?
RTE Studio 4 at Montrose could have been used. At just over 6,500 Sq Ft it could have fitted an adapted form of the British set, along with wide angle camera lenses to make it look bigger.
RTE also have two sound stages, at just under 6,000 Sq Ft each, they could have used one of them.
I do not see RTE using the British set, as this would have meant flying out the Irish contestants to London, a production cost which would have bankrupted RTE fast giving the state of their finances, even in 2000.