Crap phone signal in a static caravan

[Techwizzard]

My family and I own a caravan at a local Holiday Park whenever I go on the internet on my phone when we are at the caravan the connection is pretty crap, it's alright for phone calls, but it's not for going on the internet and using apps Is there anything I can do?

[MI5]

@Techwizzard 

You can try using 3g as most of O2's 4g infrastructure is saturated.

Otherwise, change provider is about your only option.