Smarty in Oxford (not so smart)

Living in Oxford for over a year now and the signal is terrible. I live nr Iffley but the signal is terrible from Heyford Hill Sainsbury's through Iffley road and Oxford City centre. This is to the point where there is often no access to the internet be this inside or outside of a building. There are no down cells.

I find it surprising that a city that is visited by so many people and also have a largish population would be so poorly served. 

I have looked about and whilst I can find potential reasons for some of the coverage issues, it doesn't explain all not can I find any detail on a resolution method or date; can anyone please help before I change provide? Thank you.