Scubawasp
The official document is Appendix 2 and 3 to JAR-FCL 1.125. This is further amplified in AIC 67/1999 available on line at:
http://www.ais.org.uk/aes/pubs/aip/pdf/aic/4W355.PDF
You can also download the application form from:
http://www.caa.co.uk/docs/33/FORSRG1111.pdf
You do not have to be a FTO, you just have to register as a facility, that can be one person, a club or a school.