Followed the steps in the post listed in the response, i.e. DROP TABLE wp_display_slider_menu ; and then recreate the slider items in WordPress > Frontpage Slider and everything works again. I forgot to mention that I too swapped from Windows Hosting to Linux Hosting.
Thanks for the quick reply, I have done as you suggested and replaced the theme with the latest version. Unfortunately it made no difference. , nothing saves in the option panel, I will have to investigate the other post further.