I want to know if there is a centralised community site where all Hardware is listed in terms of compatability with Linux. Something like AppDB for Wine.
Centralized I don't think so.
But maybe this one is something you are looking for.
But there are some sites:
And the Debian Hardware Portal
And an older list
And most likely there are compatibility lists on every major distributions' site/forum. And some specialized sites like for TV-tuners
The biggest database of Linux-compatible hardware is here: http://linux-hardware.org/
Timeline of tested computers: http://linux-hardware.org/index.php?view=timeline
The tool to analyze and count your computer: https://github.com/linuxhw/hw-probe
There are about 4500 computers in the database (Feb 2016). Search for interested hardware device and read system logs in the appropriate probe in order to check for Linux-compatibility.