The link that Offred provided shows that other bodies / people are also allowed to provide the letter
“the courts
the police
a multi-agency risk assessment conference (MARAC)
social services
a health professional, eg a doctor, nurse, midwife, psychologist or health visitor
a refuge manager
a domestic violence support service
your bank, eg credit card accounts, loan documents and statements
your employer, or education or training provider
the provider of any benefits you’ve received”
That said, I think the state should pay for GPs to write these letters if they are made aware of DV suffered by one of their patients.
Surely this should be more widely discussed. If the government was able to react to the premium rate phone numbers for job seekers and make the calls free, they should be able to waive the fees for helping the most vulnerable people in our society - women & children facing domestic abuse