I used the following site to get my tickets, there is an option at the top of the page to translate the page to English. As for your tickets I normally print them off myself nearer to the GP. I have been to the Prague GP for the last couple of years and have sat in the B section the first year then the A section last year, seemed to be plenty Brits round me, though there were Union Jacks round the track so there doesn't look to be specifically one place.
https://www.ticketportal.cz/performance.aspx?idp=260015