Land Rover Logic:
SE Special/standard Edition
HSE High Specification Edition
DSE Diesel Special/standard Edition
DT Turbo Diesel / Diesel Turbo according to them (must be lost in the German Translation)
DHSE Diesel....You guessed it.
DHSE tends to be later years standard but options as Data mentioned can still be added or taken away.
Try giving it a good thrash might be just crap on the turbo or in the exhaust - throw in some good fuel system cleaner to.
or
SE - Shi*y Engine
HSE - High Speed Embolisim
DSE - Digital Shi*y Engine
DHSE - Dont hold the Steering Equipment
DT - Dont (even) Try...