Not so. I live in France.
The Republic of Ireland is in the European Union. They accept payment in € and in £ as a lot of their business is with the UK. I pay £12 (or €18 ) delivery to France i and that's for 30 Kg. True, the 25Kg bag prices are within €5-6 euros of each other, but if you buy by the kilo it's much cheaper eg. Maris Otter is €15.31 for 5 Kg from Autobrasseur France and it's €16.94 for 10 Kg from thehomebrewcompany. Hops are much cheaper, too.
Crossmyloof is in Glasgow. Yeast and hops don't attract import duty and I've never had a problem. If you buy, say 10 sachets of yeast you can get them down to about £1 a sachet or less, depending on the yeast. Hops are a little dearer, but that's to offset the "free" postage. In fact postage is free in the UK, but I've never paid more than £5 for tracked delivery for up to a kilo of hops. And both company's have a discount code for being a member of this forum, 5% and 10% respectively.
Well worth a look.
Just had a look at Más Malta website masmalta.com. Prices are about the same as here in France. You really need English malt for English bitters, but it doesn't have to be Maris Otter. True, I use Hookhead, which is Irish, but it's just as good. German and Belgian Pale malts are quite different and, when times are hard, I prefer to use Belgian "pilsner" malt instead of their pale malt for making bitters. But I'm unlikely to run out as I'm well stocked up.