There are several free film screenings in London this Autumn with the Peckham & Nunhead FFF and the Charlton & Woolwich FFF (FFF = Free Film Festival, whose overarching website is www.freefilmfestivals.org). Also some £5 fundraising screenings in Streatham too. There are loads of FFF all over the place at different times of the year.
August: www.freefilmfestivals.org/whats-on/?view=cal&calmonth=8&calyear=2018
September: www.freefilmfestivals.org/whats-on/?view=cal&calmonth=9&calyear=2018
This year I'm helping out with the C&WFFF and I'm putting on a screening myself at Charlton House, a lovely Jacobean house in Charlton Village (btwn Blackheath Standard and Lewisham). My film is The Dish, on 14 September - we'll also have the Flamsteed Astronomical Society along with some telescopes for people to look at / through beforehand. I'm quite excited!
Anyway if free films are your sort of thing.. check out the listings. There are plenty of family-friendly screenings too. Mine's a Cert 12 (some swearing) and is an outdoor screening, with subtitles. If the weather is bad it'll be an indoor screening as I've booked the library just in case.
Jo 