Yes it's interesting how Brexit affects so many of us, isn't it? Correct me if I'm wrong but as I understand it if your purchase from the UK to Ireland (inc postage I fear) is under €22 it won't attract import duty. I realise that 22 euros doesn't go very far if it includes postage too.
I think that strictly speaking the UK supplier should subtract the UK VAT and then the Irish 'VAT' should be added in Ireland. I read that An Post is charging a handling fee of €3.50 on top of the tax owed to collect this. This is better than the equivalent £8 handling fee we are charged in the UK when we have to pay import duty. So if it works according to my understanding it shouldn't be too bad. However I do wonder how many small suppliers are already set up to do this. Big suppliers will be I'm sure. For instance I read that Selfridges are set up to send things to Ireland and they sort out the tax stuff when you do the online purchase so you don't have to sort out anything at the other end and you know exactly what you are paying up front.
I think this is the sort of thing which will get more smooth as time goes on. It'll have to. Meanwhile you lucky Irish peeps can continue to buy from European sites all in Euros and no further tax. I've been a great fan of Driessenstoffen (with my winkelwagen, remember?). They have lovely stuff at really good prices and with a flat postage fee of €9.95 to the UK (which isn't bad if you have accidentally tipped 10m of fabric into your winkelwagan
). Presumably the postage costs to Ireland are similar. I don't know how it will be for Brits buying from them now. Luckily I've already been round with my winkelwagen a good few times already while we were still in the transition period!