I’m cooked - reference hasn't arrived

You can apply without a reference - once they get your application, your Unis will then contact you to ask for a reference.
Btw, have you checked that the Unis you are applying to will actually accept weak A level grades plus another Uni's Foundation course - many top Unis won't.

yeah, i’ve emailed them beforehand, i applied to the ones that said they’ll consider foundation year students. Although i didn’t tell them what grades i got cos i thought that if i mentioned i’m doing a foundation year it was implied that i didn’t get the entry requirements? I prob should’ve but it’s too late now ig

You need to declare all grades/qualifications on UCAS AFAIK (assuming that you’re applying via UCAS). Intentionally skipping grades could be deemed as fraudulent application and could have it rejected unless I’m mistaken here.

Even if it wasn’t required, it’s not a good outlook for you to have intentionally done this and misled the uni(s) regardless.

I believe OP was referring to the correspondence they have had with the unis to check that they accept foundation years from other universities, not the actual UCAS application (in which they have hopefully put their A-level grades, because you're right in that they have to).

You need to declare all grades/qualifications on UCAS AFAIK (assuming that you’re applying via UCAS). Intentionally skipping grades could be deemed as fraudulent application and could have it rejected unless I’m mistaken here.
Even if it wasn’t required, it’s not a good outlook for you to have intentionally done this and misled the uni(s) regardless.