*tea accepted with gratitude*
They were about 10 yards away, or maybe a bit more, so the camera (a Sony 2.3 MP compact) was at the maximum optical (3x) and digital (2x) zoom. I was very pleased with the way they came out, as they looked a bit rubbish on the LCD.
A valid point on the Hi-Viz, but Whipsnade is only open during daylight. Annoyingly, they ban most forms of wheeled transport in Whipsnade. No bikes, skates, miniscooters or rollerblades. Just cars. Mostly feck-off great 4x4s and GalaxyGrandVoyagerEspace megatrucks.

Perhaps the ellyfants need hi-viz after all.