there were 3 very bright and large orange lights travelling in line astern at fast speed and low altitude, all were totally silent.

They approached roughly from the west, in line astern 2 front ones fairly close together, the rear object some distance behind. All were totally silent (I am used to military jets flying over this region, and all make noise), fairly low altitude and then as I stopped to point them out to an elderly couple, they changed direction to head roughly north, and hte lead 'light' accelerated and climbed to higher altitude, again completely silent.

I stood still watching these lights approach, change direction and zoom climb away, for about 3 minutes. I took several photos, but without zoom lens so the lights have come out as small dots in the pic. I would have thought they were military jets by being in formation and at the speed they were going, but were totally silent unlike any military jet I've yet come across.