If you have a plastic enclosure then this will be the ARM Controller MKI or the original Pic controller inside. If it has the black aluminium enclosure then it would be the ARM Controller MKII
Each controller has it’s own software and firmware. You can check the downloads page for more details http://www.ukcnc.net/index.php/downloads/
To double check, you can open up your enclosure and check.
The ARM Controller MKII will look like the picture below
The ARM Controller MKI will look like the picture below
The old Pic Controller will look like the picture below