There is a bright light in the south-western sky, possibly Jupiter, but I'm not sure. I saw a tiny star near but noticed that it was moving in an orbital trajectory round the suspected Jupiter. No terrestrial aeroplane or helecopter would do such a thing.

I first noticed it at about 6 o'clock to the bright stellar object and it went round to about 10 o'clock then dissappeared.

I realised that it couldn't have been orbiting the stellar object as it's speed would have been rediculous and if the stellar object is in fact Jupiter it would have had to be ludicrously massive. If it was travelling at a "conventional" speed it must've been about 10,000 feet up and going from a horizontal to a vertical trajectory is pretty short order!