Looks like Restaurant is available for self-hosted sites through Organic Themes here:
If you purchased Restaurant on WordPress.com within the last 30 days, you can issue yourself a refund in your dashboard under Store > My Upgrades.
Some sellers are able to offer discounts on the self-hosted version of their themes under certain circumstances – for Restaurant, you may ask in this forum:
https://premium-themes.forums.wordpress.com/forum/restaurant