Not so sure myself now - I was shocked by the sudden appearance of the thing in my field of view and that, combined with the concern that I had potentially drifted into a DZ, meant I didn't spend too long looking at it once I was satisfied it wasn't a collision risk. So it could have been a paraglider, apologies for wasting your time if that is indeed what it was.
In any case, the time was 14:42z on 11/11/2016 and I think the location was just east of the bird sanctuary on that chart screenshot I posted, close to the M40.