You will need to phone the NowTV Broadband Team, where they will check if it's possible at your post code address.
Whilst signed in on here, go to My Account, then select Broadband & Calls, then click the drop down arrow below your broadband plan, then click the " change my broadband " button to reveal the telephone number to call.
Are you a NowTV Broadband customer ?
If so and there is nothing shown under My Account > Broadband & Calls then go to Orders & Appointments section instead on your account and click the drop down arrow below your live activation date to reveal the telephone number to call.
If you are an existing NowTV Broadband customer then usually the telephone number for the Broadband Team are usually contained in the sections that i listed previously.
Maybe try this link below, where if you sign in with your NowTV Broadband account a telephone number should appear on the link page.
Otherwise try live chat by clicking on the green drop down arrow below How to Get in Touch.
If you are not a current NowTV Broadband customer then there is no telephone number and live chat would be the method to contact NowTV on.
Should live chat not open or work for you then try a different internet browser with its ad blocking software disabled.
PS -Out of curiosity are you trying to get in touch with NowTV to change your NowTV Broadband plan ?