Lights in skies over london 1976

This report is decades out of date. I really should have reported it - but in 1976 in London if I mentioned it peoples assumed I was mad. 
There were about 12 of us - I can't remember - squatting in St Johns school (disussed), Richmond London, England, in the heatwave of 1976 London. These people had been telling me they had been seeing UFOs in the sky, and I did not believe them - I thought they were seeing shooting stars, satellites, aircraft etc. So I agreed to sit up with them and watch..
 At the time I was computer science student at Kingston Polytechnic.
 We dragged chaisse-longes / sofas into middle of what once was playground. The site meant that the incident lightiung/light pollution was unusually reduced for London area. Also in this heatwave the visibility was exceptional - I could see whole of milky-way clearly.
 For a couple of hours nothing much happened. We saw a few shooting stars and also some satellites which I think I identified correctlly. ACtually we saw a lot of satellites - the conditions were that good.
 At this stage I was convinced I could explain everything and they were mistaken. Them suddenly something looking like a dull orange ice hockey puck slid over from one horizon to the opposite. I thought that a bit odd but wasn't freeked. A bit later there was another similar in different trajectory. Someone claimed it was a pidgeon. I didn't think so but wasn't too impressed.
 Shortly after that the main event happened.
 We could see the consellation very cleary. It seemed an extra constellation appeared - accompanied by vague red steaks in sky according to some. The new constellation was mostly symetrical but not quite.
 It suddenly moved off - in formation and pointing "forward" (it was basically diamond-shaped but I would need to draw diagram). There was no accelleration I could see - it went from 0 to something serious instantaeneously as far as I could see.
 This formation then went clean through an angle - I'd guess about 45% or so Im not sure - with one of the "stars" taking over as leader in the change. At no time did this formation slow down during this impossible manouver.
 Then the entire formation just stopped dead instantly.
 Then the "wing" stars of the formation just took off in curved tradjectory leaving red streakes to my eyes, being replaced simultaeneously by similar incoming to make new though similar formation.
 They held that for 1 or 2 secs - then the whole lot just took off leaving red streaks to my eyes.
 I had about 10 friends with me witnessed this. I got them to write all details down. Unfortunately this has all been lost now. I quickly found if I mentioned it people thought I was mad. Some of my freinds -in fact most - saw slightly different stuff from me. I was watching one particular part of the sky. If I assume my friends were not crazy, then there was stuff going on all over the sky and I only saw one part of it. The reason I think so was that their reports just differed enough - like when we see real events.
 After this event I tried to rationalise it. The best I could come up with was lasers or car headlights shining through a temperature inversion.
 But the truth is it gave us all the serious impression of the cosmic "red arrows" - had intelligence written all over it.
 I realise I could be wrong - but I do sympathise with people who have seen stuff because I am one.