Thanks Bob for telling me what to do! Thanks LowLuster for clarification
Hotel Wireless is $20 a day and only one device can be connected, so rMBP connected
Only wireless. No ethernet connection available
So one connection, three devices and the point is very simple
on the rMBP, Internet sharing can't share Wi-fi via Wi-fi, but it can by Bluetooth PAN
MY iPad Mini can connect reliably to my rMBP and share the wireless connection and sync by Bluetooth
SO should my iPhone 5, no ifs or buts, this IS quite a basic requirement
The phone can't even maintain a proper BT pairing/connection with the rMBP let alone sync. The connection is immediatley dropped when trying and the phone say "rMBP not supported' So an Apple MacBook Pro cannot connect to an Apple iPhone 5 by Bluetooth.
As I said before "Apple this is NUTS!! this is such a basic requirement"
Thanks to anyone who can suggest a solution
Cheers Robert