Mate - No Panel or menu

[mdavies5]

V5.1 Mate on Intel HD5500 Graphics. The Live USB downloaded at great speed and started ok. I got the notification "Wireless Networks Exist" then the Blue background with no panels, menu bars etc. I could right click and change background or load a terminal. So I loaded Caja and found the desktop files to install. The installer would not load so I started the Advanced Installer. This worked fast and reported it was complete although  the progress bar showed 0%. It reformatted my existing swap partition which stuffed up booting for my existing distro. I could reboot into Sparky but I still had no Panel and no way to start any program. No way to set up networking etc so I am writing this in MInt. Any hints please or is this release buggy?
UPDATE: I installed using my external 22" monitor. When opening my laptop the menu bar was displayed. But I have a new problem. I set my ext. Monitor as default and most apps work fine. Synaptic does not display on the external monitor even though though the laptop lid is closed. Open the lid and synaptic is on the laptop screen but the mouse is correctly on the external screen. I have no problem using Debian, Mint or any other distro.