Perhaps this might be useful, though not tested on claims against AT (?):

If you are an EU customer, you could try to use the European Small Claims Procedure for claims below 2000€ or the European Order for Payment Procedure for claims above 2000€ instead of the UK Small Claims procedure. These are standardized EU procedures that are implemented in national law by the member states. As a consumer, you file the application forms with a court in your own country, not in the defendant's country. The defendant has to reject the claims within 30 days or otherwise you get a title that is enforceable in the defendants country.

You can find the forms in all EU languages on the European e-Justice Portal:

European Small Claims Procedure (below 2000€)
https://e-justice.europa.eu/content_small_claims_forms-177-en.do
European Payment Order (above 2000€)
https://e-justice.europa.eu/content_european_payment_order_forms-156-en.do

To change the language of the PDF forms, use the dropdown on the top right corner of the website.