Yes, you can, depending on airport you can check out the prices in advance.
Your limit is 1 litre for spirits though coming into Ireland.
When going from Ireland into the UK, you can get up to 4 litres duty free.
Find out about the important rules in place regarding customs regulations for people travelling to Ireland.
www.citizensinformation.ie
There are some good deals going, especially on Scotch, Rum, Bourbon, Gin, more so than Irish Whiskey.
In general, if you have an option for single malt Scotch for same distillery, go for the one with an age statement versus the 'travel exclusive'.
Feel free to start a shooting the breeze thread for recommendations
https://london-heathrow.worlddutyfree.com/en/63/liquor