Wow thanks for the quick reply!
If you're saying what I think you're saying, I don't think that will work unfortnately.
The reason being, it's not the motor that's broken, because that does turn anyway. I tried removing the motor and there wasn't anything underneath other than the bit for the 'cog' the motor spins round.
The problem seems to be with the mechanism / hinges / whatever you call them, I assume because the black plastic u shaped runner is snapped off (I removed it as it is now useless in 2 bits!).