TOPIx
From DISCO3.CO.UK Knowledge Base
TOPIx (formerly Global Technical Reference/GTR) - Land Rover's website which contains technical information, including Technical Service Bulletins (TSBs), relating to the latest Land Rover models including the Discovery 3/LR3, D4, LR4, RRS, FFRR, Freelander 2 & Defender and older models such the Discovery 1 & 2, P38, Freelander & RR Classic
Some of the most common issues for which TSB's have been issued for are discussed at Known Issues & Fixes from MY05 Onwards or at DISCO3.CO.UK Issues section which is also freely accessible.