Graham,
Thank's for your reply & welcome, appreciated. It's a standard IS200, yr 2000 i.e not modified in any way, and the garage who I know well called round various suppliers and they all said it was a HID bulb?? (whatever this is) @ c £60 each. I never thought that a simple bulb replacement could be so complicated. Replaced the main beam bulbs a few times at around £12 each, but absolutely confused as to why the normal headlamp bulbs are different and so much more expensive.