I think you might struggle to find one on here.
If you do you could try a breaker like Quarry Motors, or I think BMW sell them for just over £100 - Sopers of Lincoln or Cotswold BMW usually give a discount.
I'm not sure when BMW stopped pre-wiring for it but you'd soon find out if yours is wired by taking off the lower steering column cowl to check for the connector. If it isn't there forum member "srhutch" will make up the section of wiring for sensible money.