I`m with G.Stockton, never even heard of any suggestion that the TD5 was anything to do with BMW.
The following is from a specialist LR website. Although you`ll always get some that try to attach some cachet by association with BMW. Not on this one.
2495cc turbodiesel, overhead valve, 200TDi and 300TDi: Second time lucky for Land Rover. The lessons learned from the 2.5TD were incorporated into the new TDi engines available in the Defender and Discovery from 1990. The cylinder block still looked familiar (although strengthened internally with an aluminium ladder frame bolted to the bearing caps) but the cylinder head was all-new and a direct injection fuel system was used. These engines have gained an impressive reputation for power and durability. Defender engines produced 107bhp, Discovery engines (with different manifolding and a couple of other small changes) 111bhp. The 300TDi has a single serpentine drive belt for alternator, power steering etc, better soundproofing and a few small internal differences compare to the 200TDi. Power outputs of the two engines are identical. Though no longer offered in Europe (due to emissions regulations) the 300TDi remains available in some export markets.
2495cc turbodiesel, 5 cylinder, TD5: New and much stricter Euro emissions regulations for diesel engines led Land Rover to develop an all-new engine for the second generation Discovery, and this also found its way into the Defender. The TD5 features electronic control of the fuel injection system (with a control unit under the driver's seat), 'drive by wire' throttle and other refinements, all aimed at minimising exhaust emissions. Early reaction was mixed: the TD5 was much easier to stall than the earlier diesel engines (a characteristic shared by many of the latest generation of environment-friendly diesels) and there were reports of oil pump failures, cylinder head problems and other reliability issues - but not on anything like the scale of the 2.5TD fiasco in the Eighties. In any case, these issues appear to have been resolved, and the TD5 has turned out to be a lovely engine - much smoother than the old TDi, and it sounds better too.