Poor wifi in the house.

Hi, I've recently had Virgin Media installed in my house only to find a black spot with the wifi.

I've used the connect app to scan the house and I'm only getting approx 20mbps in the bathroom at one point it was as low as 9mbps. The connect app says that this is 'great' but as far as I know, as a Volt customer, I am supposed to get at least 30mbps everywhere. At no point in scanning the house has the app prompted that i can order the booster pods. Any help that anyone can give would be much appreciated.