During the 90s there were inbound charters to London from Linz and Graz on an outfit called Austrian Air Transport into STN. I’m pretty sure Ryanair has done each of Klagenfurt, Linz and Graz from STN.
Aside from skiing Austria seems to have fallen out of favour with UK tourists more generally. I believe Vienna used to be well within the top 10 city destinations for Brits, but by the time I went around 05/06 it was completely off the radar. I’m sure there are less summer charters to Innsbruck than there used to be as well and scheduled services are few.
It’s only really in the last 2-3 years that the number of LCC routes to Vienna has taken off. Perhaps some of that will start to rub off on the rest of the country.