ROI is its own statute
Republic of Ireland commercial late payment is not a copy-paste of the UK Act. Freelancers and SMEs usually look to the European Communities (Late Payment in Commercial Transactions) Regulations 2012 framework, commonly summarised as an ECB reference rate plus 8 percentage points for qualifying debts.
Always verify the current ECB reference figure before you claim. Tools show demo rates that must be checked.
Euro invoices, Irish clients, foreign clients
Many Dublin and wider ROI freelancers invoice in euro with IBAN/BIC. Some still bill UK companies in GBP under UK law — currency and jurisdiction are not the same thing. SortedPay lets you pick law and currency separately so a euro invoice under UK terms (or the reverse) can be modelled without lying to yourself.
What good process looks like
Issue on time. State payment terms. Remind once before due if the client is slow historically. After due date: short reminder, then a formal note with interest basis if still unpaid. Pause chase the moment they pay — that is how you avoid looking like a collections shop.