Sarah, tell the musicians at your slow session that if they go to a festival where Valmai and the rest of Spare Parts are doing a 'learn the tunes' workshop, then it's worth going to. We met them at Chippenham when we were starting to play. They put the music online in advance so you can practise, too.
At Whitby May Cheadle runs a very slow 'Not Quite Ready for a Session' and in George Garside's session he starts with well known tunes then people suggest tunes and he allows them if he thinks enough people know them - no racing allowed.