LSE has the better economics department and course, it'll offer better career prospects too. However, you'll have to weigh that up with a higher cost of living and the 'city campus experience'. Whilst in my experience most people liked going to LSE, I wouldn't say people rate it as being as enjoyable than many other unis due to the intensity of the course.
Warwick is also really good for Econ but LSE is better, Warwick is a campus uni which suits some people even if it's in the middle of nowhere (Coventry being the nearest city isn't exactly an endorsement imo but each to their own). It'll also be fair bit cheaper (lower cost of living, rather than lower tuition).
Only you know how you weigh up your preferences over course quality, career prospects, social life, campus/location, etc. I would also recommend that you put one of LSE/Warwick as a firm and then Notts/Bristol as the insurance, very little point in putting the insurance as something with similar grades given the competitiveness of Econ (if you miss your firm, it's pretty likely you'll miss the insurance too) but I'm sure you have some idea about what you're likely to get, rather than an online stranger's opinion 😅