Sucked it up and called...15 minutes of holding for less than 5 minutes of talking. She even put me on hold after I asked my question to check...
and she said that because of the 6 April change I have to use the TOC form
Her words were "Because of the recent change that form is not to be used and instead you should use the Transfer of Conditions form"
which is crappy because it's £107 instead of £40 and I literally missed it by a couple weeks
The upside? If I really wanted to pay £507 I could now do it as a same day appointment so would take the question out of how long it will take to get the new one. But I'm not made of money and the £67 extra was enough of a blow so I'll just be waiting whatever it takes.
ETA: Though I'm still confused as the guidance for TOC says:
Use this form if you are already in the UK and have a stamp or sticker in your passport confirming your permission to be here for a limited time.
The form is to apply to transfer that permission, usually because you have a new passport. This is known as a transfer of conditions (TOC).
Your permission to be here (and that of any dependants who apply with you) will be transferred to a biometric residence permit.
which I don't have a sticker, I have a BRP...but the BRP(RC) form doesn't have an option to tick change in personal details. So basically I'm just just an confused and worried I'll fill out the wrong form and waste money.
Edited again: The front of the TOC form does say "TOC by someone who already has temporary leave to enter or remain in the UK and wishes to change their personal details contained on their immigration status document or Biometric Residence Permit (BRP)" so I'm feeling better that it's the right form (though frustrated all the same)