My first aid certification runs out early next year and the re-sit is a 3 day course. No issue with that, but St John's Ambulance run a one day sports specific course. Anyone done it, is it any good etc.
As with many things it will very much depend on the instructor you get. I've found 'sports specific' courses to be very non-specific. There will be slightly more emphasis on strains, sprains and breaks and slightly less on things like hypo(er)thermia, strokes etc.
I did it once. Maybe it's different here from there but I found it's just cutting out all of the stuff which you wouldn't end up regularly seeing in a sport scenario. For example no one is likely to ingest anything poisonous while sparring, but knowing how to deal with concussions, lacerations, sprains, strains, and broken bones are par for the course. If you already have a good handle on basic first aid there's no reason not to do the one day course instead. Most urban first aid is just very basic assessment skills and then either stabilizing for transport or stabilizing until EMTs arrive and I'm certain you know how to do both.
Probably better off with the St John's course. They're usually more up to date. If you've got good basics a simple 1 day refresher will do.
I guess it wouldn't hurt to do both. Just for further "insurance" purposes, even if it would feel like you're being taught how to suck eggs. All first aid is based on stablisation before the Pro's come in anyway and recognising specific injuries. My First Aid, also covers head and neck injuries from vehicle collissions, with a specific focus on those wearing motorbike helmets. If your normal first aid covers that as well, then it should be also suitable for those with concussions and neck injuries. (with scaling based on severity etc)
Which is probably one of the key motivators in needing the first aid. More poked eyes than a wing chun ninjutsu cross training seminar.