Hi, OP and @pinkdelight
I am a former Russell Group STEM admissions tutor. My School is very competitive with an offer above AAA. We sometimes must accept applicants who don’t quite make the offer but very seldom go into Clearing.
This is tricky. ‘Top university’ doesn’t have a precise definition, and the space between what admissions requirement a degree programme publishes and what it will accept can vary widely. At one extreme, Oxford’s standard offer is AAA but successful applicants mostly have (significantly) higher PGs as well as excellent scores on admissions tests. OTOH I hesitate to guess at the lower bound for achieved grades of students on some programmes with published AAA requirements. UCAS and the Complete University Guide show the achieved grades of recent cohorts on degree programmes. Note that this includes students on contextual offers.
Back when I was an admissions tutor and my programme was climbing the rankings, we stuck on AAA for a little while. We always had enough applications to reject out of hand everyone with PGs more than 2 grades off, and most years everyone more than 1 grade off. (We applied the same principle to contextual offers, obviously from a lower base) We considered cases at the borderline carefully on an individual basis. Now with our very high offer, in a good year we reject everyone (barring Mit Circs and contextual offers) who doesn’t meet it.
It may sound harsh, but it is no favour to accept someone who isn’t working to the admissions standard. The large majority of PGs are overpredicted (more now than when I was doing the job). All admissions tutors know it is much worse to be shut out in August and have only Clearing options than to give yourself realistic options to start with. After all, anyone is free to use Clearing.
An A star in your chosen subject is fantastic, of course. In a very competitive situation Astar B does not count for an AA requirement, but if bums are needed on seats it is a substitution we are all delighted to make. Unfortunately the D is a real sticking point.
However AAC and Astar BC are good sets of grades! If DD can achieve either of these she will have better (realistic) options applying next year with grades in hand. She could also pick up a new A level, to complete in one year, and submit her application in Jan with a new PG, if this appeals.
DD will get through this, OP, although I am sure it is stressful right now. Note that many YP resist the idea of a gap year on the grounds that they will be a year behind their friends. Long experience shows that a portion of those friends going right off to uni will experience delays of some type, or drop out. If it takes an extra year now to get things right, that’s nothing as against setting yourself up to succeed in life. Also, the students who have done a gap year tend to adjust better to uni, become informal leaders, etc. I wish more of them did it!