got the seal kits from the fettle box for my Optimus 45 and SVEA 5. I had been messing about with them trying them out, and they just wouldn't work properly. I fitted the new seals and the difference is truly amazing. I'm guessing the old seals were letting just enough pressure out to affect performance. I've a Hipolito stove to fit new seals to now so I'll see you guys later.
i found the same thing! a couple new seals in easy places like the filler cap made a so-so stove run like new..