Not Familar with Dublin prices, but I would price it for €1220 + VAT.
€120 per rad inc radaitor, TRV and convertor, from GB to copper. It would mean your radiators are hung slighty higher than now.
€350 Labour, It would need to be complete in one day, returning on a second day would may draining and refilling system, time consuming work.
€30 for inhibitor.
Having GB piping makes the job more complicated.
If you wanted the old radiators to be taken by installer, this would be extra. Our local recycle place charge around €15 to dump there, plus time.