So about €66k in CGT. (Just over a years rental income).
Well, the rental income is subject to tax so it's more like two years' net rental income assuming you have pensions and other income which use up your 20% tax band.
Of course, any gains in the new property you buy will be exempt from CGT.
And there is no CGT on death. So if you die while owning the first property, the liability to CGT would disappear.
There is one big downside to holding onto the house. You have €1.5m in profit in the house today and there is no CGT.
If you sell it after 5 years, and house prices have not changed, you will be liable for €66k CGT.
So it might be worth selling it now.
If you are buying another house, you should probably diversify by buying shares. If you need cash, you can sell some of the shares. It is very likely that you would still have most of these shares when you die, so the CGT would disappear. If you hold onto your house and need cash, you have to sell the whole house triggering the CGT liability.
However - as you have considerable wealth, you should probably sit down with a Chartered Financial Planner and work out how best to plan for the future.
Brendan