Aybody got any heater knobs lying about? My Sister has bust one on her car (87 BX 19RD Estate - best described as 'rough'!!). I think the mech is OK as she has been using the fan knob interchangeably with the direction knob. I suspect a combination of age and heavy handedness.... The bust one is grey, but any colour will do.
Was out in it at the weekend - the ride is much better than my 97 VSX Xantia Bit more rattly and noisy though
I've had the same problem. But with a little Araldite and some soft iron wire, the sort florists use, I fixed it. Araldite it together, then bind with the wire, which makes it last. Don't use too much wire, or the knob won't go back in the hole.
The little flat spring can be replaced with a piece of snapped off worn junior hacksaw blade.
Bit more rattly and noisy though 
