Thanks for the link Marcelo. Yes, that is the adapter for which I was hoping there's an alternative! Ah well, it prevents the machine becoming a 'paperweight' so I'll order one and see how it goes.

It's possible the angle of the beam on the Osram bulb is too wide. The width of the light-path seems quite narrow and if the reflector doesn't have a tight beam then a lot of light will never reach the inside of the mixing-box. I'll be doubly sure to locate the new Philips bulb....