Aurea - congrats to your DS. Even if it's his third choice, it'll give him something to think about ahead of hearing from Cambridge and Edinburgh.
Parmaviolets13 - don't panic, it depends on a lot, uni, application process and number of applicants.DD's first offer was 11 days after application, her second 42 days after (the latter of which we had understood wouldn't be decided on until after 15 Jan). She does know a another decision is due within two weeks as they state their timescale clearly. However, I do know one of the courses she's applied for issued mid/end March for 2018 and I think she'll be waiting on that decision.