UPDATE 23/11/2020: In May 2020, Oxfordshire County Council withdrew its trans-gender toolkit, pending legal action. In the light of this decision, I recommend that schools speak to their legal provider before making policy decision with regard to supporting students who identify as trans-gender. (For the Oxfordshire case, see here: Oxfordshire council transgender guide scrapped after girl's court case)
Talking to colleagues around the country, many schools are seeing pupils who are describing themselves as transgender. This raises a number of issues when supporting transgender children in schools. This is not a topic within my personal experience, but colleagues who have, recommended these websites and resources to find out more.
Directory of local groups
Resource Packs for schools