Welcome FlyerTalk Robbo2302, it’s lovely to see you here and I hope you continue joining in discussions. I wouldn’t worry, I’ve noticed no difference in Ryanair seatbelt sizes compared to other airlines. If you find the seatbelt works well for you on other airlines (either with or without an extension) then I’m sure you’ll have the same experience with Ryanair. Please feel free to come back and report your experience.