I'd heartily endorse icant 's points, particularly those around accommodation.
On that front I'd add that tuition fees are not the big deal, £9,000 or £90,000 makes no difference in the short term, but at the outset that £9k annual tuition fee figure was probably what worried myself and DH most in terms of finance. Totally unwarranted fears. On the other hand once accommodation costs starting coming out of the woodwork to go with other living costs allied to the limits on student loan / grant, and relatively low household income thresholds that is something worth really understanding early on.
The student finance website has a useful maintenance loan calculator, worth bearing in mind that its household taxable income, and that it tapers off quite quickly. Two earners, even though basic rate taxpayers, could be in for a nasty surprise. I'd recommend being aware of that sooner rather than later.
Durham University.....is very highly rated and an excellent institution, DS1 really liked it and had it as his insurance. However as the OP points out unlike many Uni's they wait until the mid Jan deadline before starting to make offers, and then take their time about that. They have the added complication of course department(s) decision then glorified halls of residence college allocation. It can take quite a long time and some departments seem quicker than others.
On point 6, MN is great for support, but don't take everything as gospel. What is true for one uni may well differ for another. MNers have very useful experience of the Uni's that their DC has applied to / visited, but don't assume that what is said about one uni can necessarily be applied across the board.
As a new 7th point worth knowing exactly how the grades and A*s etc are calculated between AS and A2.
Finally, begging forgiveness for such a long post, never feel that there is not a place for
and
through y13. In moderation of course :)