I have been making enquiries about this option and have discovered a much cheaper way of travelling to Cape Point.
The average price of this tour is around R650.00 p.person at the moment....but if you take a train to Simonstown, which costs R25.00 pp. for a return ticket you can then take a transfer to Cape Point for about R450.00pp.incl. entrance fee
Transport bookings can be made from Cape Town Tourisms' Simonstown information office.
It turns out that this option is now hugely popular