I think you're generally reading a bit too much into this, in terms of economics and finance the general tiers are:
Tier 1 (targets) - Oxbridge, LSE, UCL Warwick and Imperial (Imperial only for finance not Econ)
Tier 2 (upper semi-targets) - Nottingham, Bristol, Durham, Bath
Tier 3 (lower semi-targets) - kings (doesn't specialise in Econ/Fin), Manchester, Exeter, Edinburgh, St Andrews.
The rest are all non-targets, can still make it in but harder.
So all the ones you're speaking about a very very similar so going to any of them isn't gonna make much difference at all, banks and economic institutions care far more about your work experience/internships and how well you perform in their own assessments then the specific uni, especially when all the unis you've mentioned are so close.
In terms of Nottingham specifically, I'd probably say Bath and Bristol have ever so slightly more rigorous economics undergrad degrees but you're really splitting hairs at this point. So I'd generally say Bristol > Bath > Nottingham > Durham but as I said it's very close.
In terms of placing students into banks at graduate level, Nottingham probably has the best placement record, followed by Bath then Bristol then Durham. In terms of actual economics departments (so including postgrad rep) Nottingham is definitely the best, then Bristol, then Bath then Durham. Durham is actually surprisingly not that fantastic for economics but the prestige helps it. At overall department level Durham isn't even close to a top10 but it's undergrad program is decent enough but not better than those in its tier.
FYI I'm pretty sure Manchester university has the highest student population. Hopefully this helps a bit