The Bluetooth system in the Lexus is not the best - and it has many "things which can be improved on", e.g. the transfer of phone numbers, which for example in a BMW is automatic.
Any way, I cannot help you with the problem of downloading numbers to your car - other than suggesting that you do them one at a time and store them as separate names (maybe by putting extra spaces at the end of each name.
Now with regards to the number not coming up when the car is moving. This is true. However, if you have the name stored with the number, then the name will come up when the car is moving (thus the reason why you should transfer numbers over to the car). Please note, however, if you transfer the number over as +44.... the name will not come up. You have to store the number as 020...
Yes, you can only dial 18 numbers (well, 17 actually as one of the 18 is a Last Dialled Number). Again, unlike the BMW where you have a keypad and can dial numbers even when moving - and can access the phone book.
Anyway, heres to hoping that Lexus come up with some upgrades to the Bluetooth system to make it more like the BMWs...
Regards