Birmingham is boring although they are going through a logistical, transport and facility transformation (not enough to catch up with Manchester's runaway success to retain it's second city status). We will see what happens after the city centre's transformation and HS2 in 10 years time. I have lived their 18 ish years. However, apparently it's the 3rd happiest city.
If you want the city life equivalent to large cities abroad with relatively low rent costs, commute from zone 4-6 to your London workplace.
Edinburgh could be interesting and is an alternative to the above. You may want to account for the instability with respect to national sovereignty. Bristol seem great as well.
York, Bath, Oxford, Durham, Cambridge seem like fantastic cities if you want to live near great views, the countryside and historical architecture.
EDIT: It was interesting to observe, whilst visiting Germany in the past week, the German perspective of the British European referendum with its slogans 'Bye Bye Britain' across newspapers and their TV stations.
