poor data and phone signal

[Webb354]

i have checked thew sky connection checker and it say that i should have good coverage both indoors and outside but i get 1 bar with or without 3 or 4G. have done all of the online advice with regards to settings and still no better. the phone call didn't help at all as it just cut me off every time. 

Anyone have any useful advice that is different from what is already offered via the website?

My location is Bovington