Hi I was recently sourcing quotations for wooden sash windows and I was only able to find 3 companies in Dublin who repair or make wooden sash windows. Both have been mentioned already, the other was craftcarpenters.ie. I found they are all busy (their lead times are also unfortunately several weeks) but I managed to get quotes from them all.
Like Carpenter, I believe the wooden sash windows are far superior, authentic (and more beautiful) than the PVC sash windows. They are also more amenable to repairs in the future, whereas PVC windows need to be fully replaced. Not only do they enhance your house, they enhance the street on which you live.
Your 3-windowed bay window sounds beautiful, it would be a shame to replace these windows with PVC. I think if you can stick with the wooden sashes you'll be doing your windows and the house far more justice.
For the record, I bought a lovely old redbrick with intact fireplaces and other beautiful period features and was absolutely disgusted that the original sash windows had been replaced with the most hideous PVC windows. Before I even purchased the house I knew that I HAD to replace the ugly windows. Not only that but when I looked inside the house, the archetraves had been altered to accommodate the ugly offenders, it is such a shame. I will be restoring my windows to their former glory very soon. When thinking about the cost of replacing your windows, you should also consider the value that sash windows will add to your property in the future. You only need to read the property pages to see that original sash windows are highly sought after features, and the more that time goes on they will be even more highly sought after. Even the glass itself in your windows is an antiquity and costs approx €190 per square foot I believe to purchase from salvage yards I believe! I hope this helps. Please try and do the right thing by your house..