Poor Connection and Slow Speeds

[Ben+Denby]

Hi

I have Fibre broadband which is sent to a box at the side of my property (via telephone line, not underground)

We have two boosters in the house as well as 3 Sky Q min boxes as the connection through the house is very intermittent. Usually poor, occasionally very poor.

Here are my stats, I have a black router 

I have turned off/on the router and this doesnt seem to make a difference.

Any help would be appreciated.

Thanks