I am not sure if this will fully comply with the Coding requirements, but we have just bought a couple of kits form the following supplier:
We operate a coded boat and the 1st aid kit is supplied by our marine people in a sealed pack, as is mentioned earlier? So for those cut fingers or little burns we have just had a small ARCO pack. This is not w/proof and does not like damp...
We have bought a couple of these 2day at the Boat Show, so I cannot fully endorse at this stage, but they are rather sensibly (IMHO) graded in a 'Time from Help' system ie. 30, 50 or 180 mins from assistance. I liked that. I also liked the inclusion of eye/wound wash, instant ice packs and burn gels.
They do them in the Ortleib/Flexi waterproof packs or the hard Peli cases. Refills are available, and you could easily use one as you main kit if you had a w/proof or Peli case spare.
Bit of rave review on little info I know, but they knew what they were talking about and had definitely spotted a niche that needed filling.
Might be worth a look?