urgent predicted grades help as a reapplicant

i'll try and keep this as short as possible, but i really really need help asap. basically i'm reapplying for a university that has a guaranteed offer scheme that i'll be eligible for so long as i meet the lnat and predicted grades requirements. i sat three a levels in the 2025 cycle and missed my offer by a few marks, so i'm teaching myself a new subject and sitting the exam through a tutoring company next year. i will be sitting a mock exam through this company in late december/early january next year.

now, the university says they need predicted grades via ucas/a referee. if i apply as a private candidate, the tutoring company can send the predicted grade to the university directly, they can't act as a reference to private candidates. i can't really apply through my old sixth form as their internal deadline is early december and i just won't be ready to sit paper 1 and 2 of a new subject by mid november (takes time to mark the mock exams ofc).

so if i apply privately and the tutoring company sends the predicted grade to the uni, will this still ensure i make the guaranteed offer? or is literally ucas only? i'll also try and get my old school to send last year's references but idk if they will. i can email the uni but they took like a month to reply last time, i could call but i want the answer in writing to be safe. (i doubt they'll give me an offer without the guaranteed element).