Hi tyunnos, my ds applied to those three last year with results. Application went in before Christmas and he heard from St Andrews first with a no. Got an alternative offer from Durham, prob in March I think, an offer from Edinburgh soon after. I felt sure that they would treat them differently but it didn't seem to work that way. Same wait as everyone else I'm afraid but it was for a very competitive subject. HTH.
I know of someone who applied to UCL ( so not one of your choices but in case it helps ) post A levels - he heard about the same time of year as DS who applied pre results. I am sure you ( DC) would like to know , but I think no need to worry just yet !
Rainbows, I suspect it is more that they wait till mid-January to see who has applied. They have a legal and UCAS obligation to treat all EU applicants who apply before the January deadline equally. So competitive courses at Durham, UCL, Warwick, Bristol, LSE etc will want to see who has applied before ranking them. Particularly when EU numbers are so unpredictable.
As people firm Oxbridge and other Universities, places open up. But it can be a slow process. Both DC were waiting till mid March for three of their choices (economics and medicine) both with A* predictions. One got one, the other two, so a sort of 50% ratio.
The Student Room can be helpful in reassuring an applicant that they are far from alone.