Under GDPR you're entitled to accecss your own records free of charge. this is effectively what an SAR is. Requesting a copy, or requesting them to send a copy is not the same as them producing a new report or providing any further service.
They're allowed to charge for non
NHS services like writing up reports to be sent to other private practices as they can be considered outside of th
NHS Contract but your
SOC IS a
NHS provided service.
It sounds like they're trying to use the fact they're sending it to a 3rd party as a reason to try and charge you in the hope you don't know your rights and will simply back down and pay.
Go back to your
GP and clarify the following:
1) Confirm you're requesting an existing
SCR and that they are not preparing any kind of new report.
if they confirm its just your
SCR then reiterate that unless its reasonably considered "excessive" then it falls within the remit of their
NHS contract to provide it to you for free.
If they are suggesting its a whole new report, just submit an SAR and then they have to provide it legally, for free, within 30 days unless other circumstances apply. Contact the practice ISO with a template SAR for your records (plenty online or with AI). Also bring this to the attention of the practice manager.
If they still refuse, submit a complaint via the ICO and explain you're being paywalled for your own lawful SAR. and you are now actively being denied your legal rights.
They will often speak to the practice and ask them to send it over in a civil way before things escalate.
The other alternative is trying to contact the
NHS directly for help in retrieving your
SCR via
england.contactus@nhs.net (include in the sub line - “For the attention of the Subject Access Request team”)