constant white light over bristol (uk) with right angle returns

one white light traveling from south to north very fast. it then instantly returned back to half way point then turn at a near right angle turn to travel west. the light then moved back to central point and then travelled in a north to south direction before disappearing. viewing conditions were intermittent clouds and the object was above the clouds.  first viewed looking south at about 45 degrees object travelled north to about 80 degrees and zipped back. finally repeated south to north and south direction before disappearing. first time reporters so help this helps