Here are some links you might find useful for your research into setting up an RYA school:

Setting up an RYA school:
http://www.ryatraining.org/runningcourses/trainingcentres/settingupatc/

Fees to set up an RYA school:
http://www.ryatraining.org/runningcourses/trainingcentres/settingupatc/fees.htm

Adventure Activities Licencing Authority:
http://www.aals.org.uk/

Reporting a RIDDOR incident (Reporting of injuries, diseases & dangerous occurances regulations):
http://www.hse.gov.uk/riddor/index.htm

Guide to writing risk assessments:
http://www.hse.gov.uk/risk/fivesteps.htm

Criminal records bureau:
http://www.crb.gov.uk/

RYA Criminal records disclosures links page:
http://www.rya.org.uk/WorkingWithUs/childprotection/Disclosures.htm

RYA Child Protection Guidelines (these guidelines can be copied/adapted to suit your centres needs):
http://www.rya.org.uk/assets/chiefexec/Web%20Documents/Child%20Protection/RYA%20Child%20Protection%20Policy%20and%20Guidelines%202007.pdf

Free RYA child protection posters (maximum 2 per centre/club) http://www.rya.org.uk/WorkingWithUs/childprotection/Pages/poster.aspx

Example Insurance brokers:

Bishop Skinner Marine:
http://www.bishopskinner.com/

Mardon Marine:
http://www.mardon.co.uk/