Haha yeah I did swap the bulbs around and the result was unfortunately the same. I've got a mountain of paper work that came with the car, with receipts for everything, and I can't find anything suggesting there has been a replacement headlight, but it is still possible.
These Osram LEDs have a very good cutoff and appear brighter and clearer than the previous bulbs that came with the car, although I'm aware that could just be the white effect. one bulb was an Osram Original Line and the other a Philips Long Life Eco Vision, so not the best anyway. I wanted better lights, but as they are annoying to change, my plan had been to replace the dips with Philips Ultinon LEDs. I figured this would get around the current MOT requirement 4.1.4 as
"Existing halogen headlamp units on vehicles first used on or after 1 April 1986 must not be converted to be used with high intensity discharge (HID) or light emitting diode (LED) bulbs. If such a conversion has been done, you must fail the headlamp for light source and lamp not compatible." With the lenses on the dips being transluscent, it's not possible to see the actual bulb, so I'd leave these in for MOT and hope it passes. With main beams being easily accessible, I'd put halogens in there for MOT then swap the LEDs back in afterwards
The car is in for it's MOT right now, so I'll provide an update on whether the lights pass or not. It may fail though due to the dips being slightly different colours as they need to be a "...matched pair of dipped-beam headlamps... ...Lamps are matched if they: emit light of substantially the same colour and intensity...".
I actually went with the Osram LEDriving HL BRIGHT for two reasons. Firstly I couldn't get the H1 retaining clip to fit around the Philips LED base. I'd bookmarked the Philips as a replacement last summer, but after finding they didn't fit last friday I discovered that end of last year Osram had released the LEDriving range, and at less than half the cost of the Philips Ultinon 9100 range, but with the same luminous flux and expected liftime. I sent the Philips back and have found that the Osrams do fit, you've just got to force the clips around the base. It's quite fiddly but doable. You'll need to adjust the aim of the dips as they will not sit in the same position as the halogen H1s. As I fitted them only a couple of days ago I'm getting the garage to adjust them during the MOT today. Hopefully all goes well.