Thank you all for the replies however I don't think it was a skylantern.
I've seen a few of these lift off recently and whatever I saw was MUCH
brighter than them. I said 'like Venus after sunset' but this was in the
middle of the day, a bright sunlit day, so this thing must have been really
bright. Also the lanterns I saw were orange-y in colour but this was white
like reflected sunlight. I've no way of knowing how high this thing was but
I got the impression that it was really high, much higher that the lanterns
I've seen in the past. Thanks again but are there any more thoughts please?

Chris B wrote
Much like dropping your needles in the park after your fix.

Your? What are you implying? ;-)

Titian wrote
I was in Phuket, Thailand over Christmas, there were dozens of these
things floating around that night (sky lanterns)...had me totally
baffled for quite some time!

When I was in Glasgow, and sometimes when I was near other cities, I saw
lights hanging in the sky. I was baffled for a long time too. Eventually
realised they were planes coming into land and were heading 'more or less'
towards me.

Neil