Mobile phone provider with great coverage

[AndSomeForFancyDress]

Does anyone have a recommendation for a mobile data provider in Kent that has excellent coverage? We're with giffgaff and there's a giant hole in the Aylesford/Ditton area.
Many thanks.

https://www.ofcom.org.uk/mobile-coverage-checker

Thank you, @unsync . I used this and it appears there's no massive hole where we were walking yesterday.
Perhaps it's my phone....