Having a look on OpenSignal shows a mixed bag of signal reports for your street in St Helens.
Have you tried your sim card in a different handset? Have you tried TuGo ?
As
@MI5 said alway best to test signal with a PAYG sim, before committing as not everywhere has a mobile signal even these days
Indoor coverage is never guaranteed as there are so many factors involved, such as thickness in wall, as Radio Waves will only penetrate so far.
A phone wont always lock onto the nearest mast, it will hope between masts in an area, trying to find the least contention to allow you to use features.
This is not customer services and we dont have access to your account
I do not work for o2 or any VMo2 /Telefonica/Liberty Global Company