Defender - Locking Rear Axle?

Hi,
According to the TPOIx vehicle feature list for my Defender 110 TD5 it has a "LOCKING REAR AXLE". Does that mean I have an LSD or some other sort of diff lock? If so, it's not apparent - how would I be able to tell, short of removing the diff cover? BTW, I have a Salisbury rear axle if that helps!
Thanks,
Vaughn.

very unlikely to have a locking diff unless fitted as an aftermarket add on and there'd be a switch for it on dash somewhere. and possibly a air compressor as well.