Hi Fearless,
I apologise that we have not replied to you sooner. As Elias and Alvaro have already replied above, the drysuit certification or experience requirement is not due to the depth of the dive, but due to the nature of a drysuit. A drysuit is filled with air and as such really alters your buoyancy, which is why separate additional training is required.
Without this separate certification, you will not be able to participate on any of our dive tours. You can either take the drysuit course at home before you arrive in Iceland, or you can book with us to complete the course here - the course takes a full day and you can then dive other dive sites on separate days.
Please let us know if we can help you with anything esle.
Kind regards
Siobhan