"The UK Film Council have launched a ground-breaking new website, which will find out when, where and how a film is available in the UK – legally and across all formats and platforms – cinema, TV, DVD & Blu-ray sale or rental, download and streaming.
FindAnyFilm.com contains over 30,000 unique film records – which is about seven years’ worth of film at your fingertips - and is expanding on a daily basis as more films become available to watch in the UK. There are 20 genres covering everything from Action, Foreign and Classic to Thriller, Bollywood and Drama, and people can even search by inputting a mood, a location or using keywords like ‘fairytale ending’. The site also contains films in over 60 different languages ranging from English to Japanese, Hindi, Arabic, French and Cantonese."
Just don't bother searching via screenwriter unless, in the unlikely event, their name is in the summary of the film. It's only as the playwright that Peter Morgan gets mentioned for Frost/Nixon but he gets no mention for The Queen (he was nominated for every award and won the Golden Globe.)